Looks like great results painting.
I am curious though, you are painting in an open shop, open as in not a closed off area and it appears you have no exhaust set up. Are you not concerned with paint lingering airborn and then settling on everything in your shop, including the parts you just painted? Did you get much dust or other debris in your paint as it dried?
Also, body filler is not really meant to fill holes, any kind of holes. In fact it is not meant to be thicker than 1/16-1/8". I am not body guy but have worked in a body guys shop for two winters and picked his brain daily.
I think you are doing a great job so don't take my comments wrong.
Cheers