Those are looking very nice, the top obv photo is great. The focus is sharp, the lighting is well diffused with no super hot/bright or overly dark areas. Glad that you are having fun with the photo system, it can be a very satisfying hobby within the hobby. Here is a link to a site by a guy that literally wrote the book on coin photography, on this site he talks about and gives some tips on how to photograph proofs which may be of some help to you when working with the DMPL coins. Alot of the articles are very technical but in the "basic coin photography" section he discusses some great basic issues with tips and pointers.
Mark Goodman's website.