Did you see the post on creating camera lenses with SLA?
For the resin dipping in that post, the lenses were left on support bracing so that they wouldn’t need to be handled themselves.
As far as curing goes, a UV box is going to be much quicker than sunlight. Both light and heat initiate the curing process which is why we developed Form Cure. On a budget, a small cure box can be rigged which should still prove much quicker than leaving parts out in the sun.