I have Coco's ANH robe, but no Tusken until at least January.
In the meantime I've been trying something out for an inner robe with more fullness, to match that of the outer, since HT's
The Mandalorian Tusken's is quite tight fitting.
I still had a set of clothes from Kenner's 1996 12" Obi-Wan.
Taking the inner robe, I removed the elastic from inside the waist, and the belt on the outside. (The belt actually made a pretty good Afrika Korps scarf!)
Cut the sleeves off to reduce bulk, and painted it with a wash of Games Workshop Graveyard Earth, which turned it a nice, grubby sand colour.
I put it on backwards onto the body I used to dry Coco's robe on, pinning the excess material at the back with a safety pin to give me an idea of what it might look like once it had the Tusken's belt and bandoliers. There's plenty of excess material to work with.
It's hard to completely imagine at the moment, but I think it'll work. The collar may need to be cut off, since it's what was the back of Obi-Wan's costume. Though it depends whether I uses Coco's tight fitting neck wrap, or HT's fuller 'scarf' wrap.
What it doesn't have is the double layered look of the longer and shorter inner robe, but I think this could be achieved by cutting it shorter, and using the HT as the inner layer. I'll wait until I have a Tusken in hand before I start cutting anything more off.