Commercial patterns?

[Slowhand Bob]

Guys, in your experience would commercial holster patterns that recommend 8>9oz single ply leather work equally well with double thick 4>5oz leather, without having to resort to spacers in the main seam?  I am thinking specifically about some of the old commercial Tandy Slim Jim patterns.

[ChuckBurrows]

I've generally have had no problems with using doubled 4/5 oz instead of single 8/9z - you can draw a center line and then  widen the piece a bit by sliding it sideways a scosh to the side of the centerline so the extra width is in the center rather than widening both edges. I have to do this at times even with single thickness since the thickness can vary a bit anyway.