I have some packs of Wills resin dressed stone wall sheets in oo gauge. Can these be used in O gauge as I want to make a walk along the back of my diorama.
I would suspect that they could. I always felt that much of the Wills range was a bit over scale for 4mm. Try painting a single piece and pop it in place you will then get a feel for if it works or not.
I have found quite a few 00 offerings that I have incorporated in my 7mm layouts. Lighting being one such, drystone walling another. I suspect making something strictly to scale leaves it too delicate. Pete.