Thank you so much Tad!!!!!!
I'm still having a couple of issues to fully understand the first part but I can now try it out and experiment and I think that will dissipate any remaining doubts.
The other two parts I think I understand (and cool Gimp feature I didn't know about!)
In LL viewer, which doesn't have temporary uploads, maybe I can use local textures (if I don't crash like last time) before uploading the final version.
Thanks so much again for explaining it!!!!! Off to play with textures!!!!!!