I know some folks may not find this useful but for those of us that brush/roller paint a small numbers of hives I have made a VERY simple jig to paint them on. You can either hang them up to dry afterwards or rest them on 1x1's to keep them off the ground.
No paper sticking to the bottom or nothing.
I am sure I am way over thinking something simple, but I like my result.
Here it is:
4 3/4"x1" ash scrap stapled together with brads placed at the "joints" where the hive body/super will sit, keeping it from touching anything while you paint and this making less mess.