CAJUN ACCORDION DISCUSSION GROUP
Or go top a wood working tool store and get one of the rubberized sanding mats and cut it to fit your leg/box no more slidng
It's not really about it sliding, I'm just thinking it would take less strength in my hands to hold the thing. My hands aren't what they used to be after a recent flare up.
How about a lighter smaller box Say a 2 row Castagnari Lilly Or a smaller 1 row on the size of a Melodeon/Max but with lighter materials and perhaps fewer reeds Also there is a simple trick to make a "suspension" strap for the left hand Also have you considered going with 2 straps
Left thigh is what I prefer as well. Seems to be the standard method for Irish players etc. Many players spread a small blanket across their lap as well.