As part of an April 2011 walk in the Alpine National Park in Victoria, Australia, I walked from Mt. Feathertop via Diamantina Spur to Weston Hut. My guidebook does not cover this section, so here is some information about it and the nearby Niggerheads (now Jaithmathangs) that might be useful.
There are old 1:25000 and 1:50000 maps of the area but I'm assuming that you have the new 1:50000 map: "Bogong Alpine Area", Spatial Vision, 2009.
Diamantina Spur
The new map shows two tracks giving access from the Razorback to Diamantina Spur, one to the south of High Knob and one to the north. The southern track has vanished, but the northern one is clear and signposted.
The track down the higher part of Diamantina Spur is clear and generally easy to follow. It's very scenic, with great views of Mt. Feathertop. At the last knob it turns right, then bears left into a steep awkward sidle taking about twenty minutes. We got through it easily enough but it would be horrible in wet weather. Below the sidle the forest was burnt in the bushfires and there are bare tree trunks and thick regrowth which completely obscures the track. However, at ground level the track is definitely there, and mercifully the regrowth is soft and easy to push through. Contrary to rumour we had no trouble with blackberries. There is a signpost where the track emerges onto the West Kiewa Logging Road.
The new map follows the old 1:25000 map in taking the track down the wrong spur after the last knob, ending it 1200 metres north of the bridge over the Diamantina River. In fact it ends much closer to the bridge. The old 1:50000 map does not make this error.
There is no water on Diamantina Spur, and the only good camp site is right at the top. A small party could camp at the bottom, beside the bridge over the Diamantina River, but it's better to walk on to Blair Hut.
A trusted correspondent who walked Diamantina Spur in December 2018 reported that the track was clear all the way to the bottom and appeared to be being maintained.
Blair Hut and Weston Hut
Those proceeding to Cobungra Gap or Machinery Spur should be able to follow the West Kiewa Logging Road with no problems. However, the story for those proceeding to Blair Hut or Weston Hut is more complicated. First, I will describe what the new map shows, for reference, and then I will describe what is actually there.
The new map has a point where the West Kiewa Logging Road, the Kiewa River West Branch, and Blair Hut coincide. About 500 metres south of that point it shows a link track branching off the West Kiewa Logging Road to the south-east, then turning back to the north-east and meeting another track running south-east from Blair Hut which later turns north-east and goes to Weston Hut.
The truth is somewhat different. There is no direct connection from the West Kiewa Logging Road to Blair Hut. The road is a short way up the hill on the west side of the river, the hut is down low on the east side. You can see each from the other and you could bash from one to the other, but there are better ways.
First, there is an unsignposted horse track which starts at a low gap on the West Kiewa Logging Road about 300 metres north of Blair Hut and angles down gently to an easy ford about 50 metres north of the hut. After crossing the ford you are on the pleasant open area, very good for camping, that adjoins the hut. This track was clear when we followed it except for one very large fallen tree which we got over without much trouble. But if the tree is not removed and the horses stop going that way, this track might be gone by the time you read this, given that it is not on the new map.
My December 2018 correspondent used this track without trouble. There was even a signpost to it on the road, although not a permanent one. There was still a fallen tree to get over.
Second, you can go round via the link track. It's further that way, but you get to cross the river on a bridge, and the track has been improved recently. In fact, there are two link tracks, the one shown (which would suit those going straight up to Weston Hut) and a lower one (which would suit those going to Blair Hut). Presumably these branch off the West Kiewa Logging Road together and separate later (i.e. they are reincarnations of two tracks shown on the old maps), but we did not check.
As you go up the hill from Blair Hut towards Weston Hut, the first thing you come to is a vehicle bridge over a small stream. Immediately after that is a junction, with the lower link track going straight ahead and the track to Weston Hut turning left and up. Next, you meet the upper link track at a signpost. A few minutes later there is yet another junction, where a track branches off to the left. That track is on the old maps but not the new map, so I was surprised to see it looking very clear. Just go straight up the hill at each junction. There is water at the creek crossing half-way up.
Weston Hut was destroyed in the bushfires but has been rebuilt. Spring water from further up feeds a tap attached to a tree near the hut. There is a limited amount of space for tents close around the hut.
Tracks on the Niggerheads (now Jaithmathangs)
The new map shows a foot track from the point where the foot track from Weston Hut, Cobungra Gap, and Cope Saddle meets the Fainter Fire Trail, up to a lookout, across a small saddle, up to Mt. Niggerhead (now Mt. Jaithmathang), and continuing north for four kilometres, ending on the Fainter Fire Trail at Little Plain.
Sadly, this is fantasy. The only tracks in this area are the foot track from Weston Hut etc., the Fainter Fire Trail, and a foot track that starts at a signpost on the Fainter Fire Trail at Tawonga Huts and climbs to the small saddle and on to Mt. Niggerhead (now Mt. Jaithmathang), ending at the top. I have only been up to the small saddle myself; for the part north of there I am reporting information given to me by walkers I met who traversed that whole part. It's a good route, but there was no track in April 2011.