I did see that thread Barbie and it was successful for creating multiple layers for a single input layer, but not for actually blending a layer mode like Grain merge to with target layer.
Thanks for that link Saul; might try it later, but I did go ahead and manually did what I wanted an auto-script to do, but the result didn't come out the way my mind's eye thought it would. Still, I'm keeping GAP now that I got a 64-bit version that appears to work in GIMP 2.8. I'm not into animations though, so don't think I will be using it much. My motivation was with brush creation (remember the recent metal rope thread recently? lol). I'm surprised how hard it is to create a gih and make it do exactly what I wanted it to do w.r.t. a rope brush. Only partially successful. Oh well; I do like to complain.

