Nice looking install as always. I've been meaning to ask you a question about your finishing technique.....Why do you choose to use 1/2" MDF for the cover panels rather than 1/4" masonite?
The reason I ask is that I spent 10 years doing similar work and found that properly supported 1/4" provides ample support and allows you to meet the edges a lot tighter (when not fibergalssing to the edges). This is in no way meant to criticize, I think your installs are always very clean and just wonder if using 1/4" might tighten up your edging work.
This is honestly meant to be a constructive question and in no way to be criticism.