I'M NOT REALLY SUGGESTING METHS... just joshin' but fabric conditioner does soften them up alot, perhaps too much.
I used it with one of mine but wasn't wholely happy with the result so I haven't used it on the other two, I've just washed them on a gentle, cool wash cycle without the conditioner.
I don't want to give you duff advice as I'm hardly an expert. There's another thread on here somewhere that say's DO NOT EVER use Fabric conditioner on a PV Kilt (can't find it though!).
Perhaps it's best just to wash it without the conditioner a few times as you suggested in the first place. Not sure what repeated washing would do to the leather straps though.
Maybe one of us should start a new thread on this?
Edit: Found the thread mentioned above here -
http://www.xmarksthescot.com/forum/h...440/index.html Hadn't read this advice when I wanged my first kilt in the machine. Isn't hindsight a wonderful thing.
We'd better stop hijacking this thread now