I totally agree that the cloth room makes it VERY easy to fit clothing between figures. I now have a complete faith in the cloth rooms's ability to fit clothing between figures, which is a faith that I back up when first saving a 'roughly fit' object that I will import later to be fit. (you'd probably be surprised at just how very approximate some of these cloth objects are).

I've read a few bits of advice suggesting that it's best to start the fitting simulation with an object that has been scaled and positioned to eliminate poke-through. Personally I take the opposite route when fitting cloth between figures. I find that the cloth room does a better job of 'moulding' a shape in the cloth, when the simulation starts with (just a bit of) poke-through. Usually only takes a couple of frames or so before the cloth expands to fit nicely. I personally get much better results this way - rather than trying to get the cloth room to shrink clothing to fit. Only very rarely now do I find that I need to scale the character to 'grow into' the cloth during a simulation.