Cutting the plexi

I am currently trying to cut the plexi for the designed light panel but it is not easy as I thought.
The idea is to insert the picture between two sheets of plexiglas, the first one is 3mm and the second 2mm.

I did cut the 2mm sheet with a cutter but it was not easy to maintain the cutter straight enough and I had to repeat the procedure a couple of times; finally I decided that a cutter is not good enough for the 3mm sheet.
In fact, for the bigger sheet I used the dremel but I am still not 100% satisfied of the final result especially while cutting the holes for the electronic components. I have then bought a diamant tool to try again.

During Easter the main hard disk of my pc broke and I need to found a valid replacement: hopefully I didn't loose all my data! In any case I need a new HD and some time to reinstall the operating system and all the rest.