The problem is, the scaling and joint parameters are different between figures. I can jury rig M3's shirts to conform to David pretty easily with just minor tweaks for stills - the pants are a whole different matter. (That doesn't take animation into effect, either.) And it's not just a case of overall body scaling - the proportions themselves are rather different. I've run S3 clothing through the Clothing Converter so they'll fit V3 and have had to do a lot of tweaking for gaps, even after very carefully scaling everything. Cheers!