Ok so I'm wanting to have some proper sheer clothing in CC3 and iClone. Pokethrough is a constant problem though, and hide body mesh isn't applicable in this instance. The best I've managed to do so far is to iteratively sculpt in CC3 e.g. a bodysuit mesh to stop skin poke through, and refine in CC3 and resend to iClone when an animation in iClone reveals more poke-through. This generally requires a "loose fit" or scale slightly larger than 1.0 for a bodysuit, which is evident in close-ups as a "floating layer of fabric above the skin", not a tight-fitted sheer.

DAZ handles this with things like geoshells. But the difficulties and hoops to jump through bringing DAZ geoshells into CC3 are significant and basically require replacing the body texture with the geoshell texture. Workable if clunky for opaque bodysuits for example, but again, not feasible for sheer materials.

Anyone got any serious suggestions that work in practice?  The best I've come up with is to somehow "bake" the sheer cloth texture onto the skin texture, but still this will not give correct results edge on, e.g. the way stockings / pantyhose are sheer and you see skin through them when the skin is viewed face on, but are darker and more opaque when viewed at glancing angles.

SO SO SO keen for a functional solution here. It makes simple sheers like lace, nylon, fishnet, ... so difficult, yet these are really standard clothing items!

Thanks in advance :-)

Are you designing cloth items yourself? If yes, then...
Design cloth items from body mesh and try to keep vertex/edge/face relation between cloth items and body intact for the most parts. This would give you practically 1:1 skin weight transfer.
You can keep cloth as close to the body as possible without any pokes through in this case.
Of course, for certain areas, such as toes, butt.. etc, you'd have to rebuild cloth mesh joins. Also make straps, fasteners...etc. But quality skin weighting always pays off in the end.

If you're just trying to fit some existing item, then stop pulling the mesh from the body and conforming it for a moment and again spend time fixing weight paint first. But not in CC. 
Blender comes to mind first obviously. Transfer avatar with calibration clip and workout weights. Calibration clip has some extreme poses, so do not try to cover it all. Do what you can.
In some areas it is extremely hard to sync cloth weight with body weights. Use local mesh edit. Gently pull selected mesh out, when try to weight again. It's back and forth until you get it right.

Sheer items are very fragile and most of the time do not conform well on avatars other than those they were designed and skin weighted on. Conforming can mess up very fine details specially if avatar substantially different in shape.
So again, patience with local mesh edit and weights is the only way to fix it and make it look good.

Many thanks for your advice 4u2ges. Much appreciated. I have to say my experience is limited to pushing and pulling and conforming to get this piece of clothing match that character. So I think what you're saying is I'm going to need to learn a bit about how the weights work and perhaps play in blender a bit. I have to focus my time, so maybe I'll see if someone on Freelancer can help in this instance!

A repeated thanks. I learnt enough about skin weights to realise that the outfit, coming from a converted G8 female character, had slightly different weighting to the bones. I tweaked this where the outfit was changing shape with movement, and then I went through a careful process of sculpting the outfit for each  "checking" pose in iClone. The result is I think I have a really good outcome.

Good.
Couple of more tips for close fit with minimal clearance. Subdivision shrinks the body a tiny bit. And Tessellation expands it a bit.
Same goes for most of the outfit (but not always). Knowing that, helps sometimes to overcome minor pokes through of items such as stockings and other sheer items.
And sometimes body and outfit mesh subdivision level should be intact.

Also, instead of increasing the size in Conform, which can badly deform a delicate outfit, you can use flat gray tone Displacement map to expand and shrink outfit uniformly.
Normals for the outfit mesh must be uniform for this to work properly.
Note: adding displacement map might cause mesh flicking in and out in view-port, which usually does not appear on final render.

Extremely close fit and narrow view angle camera might also cause flicking and pokes through while zooming out. Those type of pokes through would actually appear on final renders.
To stop this behavior, increase Near Clipping Plane value from default 0.1 to 1 in Camera properties.

You might also consider decals. Decals can have normal maps to give a little depth, but will always by exactly "sheer" with the body itself.