I used something similar to cut my racedeck tiles and it worked perfectly and quickly. FYI I was able to rent one from Home Depot for just a few bucks.
This is what I did as well. Started at the front of my garage (most visible area) and installed moving back. Made the cuts along the back and side wall where they are less visible - though if you do the cuts right it all looks seamless anyway.
If I were to move I would definitely leave the tiles behind. Aside from it being a nice selling point of the house, I would not want to go through the exercise of boxing up all the tiles and shipping them to the next house. Part of the fun of racedeck is also choosing your color scheme and...
To be honest my gaps are probably a little uneven all around. I was willing to leave an inch or so gap in some areas to avoid extensive cutting. Most of my garage items (garbage cans, standing shelves, etc) are kept against the walls so much of the gap is covered up that way.
Honestly I dont really think about it. I am not tracking in a considerable amount of dirt and dust, but if I wanted to clean it out a shop vac should be able to **** up anything through the grates.
I just received my RaceDeck flooring last week and took the opportunity to install it over the weekend. I went with a graphite border and alloy fill and love how it came out. The installation was super easy, just click click click into place. I still have some cutting to do in a few areas but...
Quick update - I ordered the floor! I went with a 2ft graphite border with the whole center being alloy. Excited to get it and install it. I have always wanted to do something like this in my garage.