In my eyes I see nothing electrically incorrect with what you did. I'm a little unclear on the dremel and cutting down the bus bar but I think I can see what you were accomplishing in doing so. I'm also unclear how the insulators and neutral bar and ground bar were fastened to the panels. It looks ok in the picture but the Nec is pretty specific on what you can use.
I do not see a safety issue..I do see a problem (very remotely) with any issues with an insurance claim do to any fire that would be faulted to that panel.
In the end it is your choice and I won't agree with that choice but I think you did a good job considering what it would have looked like if my grandpa had done it....
" One nice thing about the NEC articles ... you have lots of choices"