Dodge
You are on the right path, without doubt. Mines is a scratch force, cobbled togehter from a variety of other armies and ranges that were available back in 2002 when I plunged headlong into this madness. The Osprey books (on the White armies) are not bad on Basmachis, as are the various travelogues from the period that you can pull up on the net. I think the 'perfect' look would be a mixture of traditional Turkic dress with elements of western dress thrown in.