I think you did the rock work perfectly. The rock does not look "off" and where it is needed you put "end" pieces n top so there are flat spots, but no flat spots at the same time. I think it will work out perfectly for you and your needs. I also use to think acros were very hard, but I am having great success with a few varieties of acros. If you can get a few frags for cheap I would go for it and see what happens.