stepped outside and took a few pics of 3/4 scale Galaga... I did not build these with exact 3/4 scale dimensions, I shrunk the original Galaga shape down to 48 inches, like the Arcade1Up cabinets, then I stretched them back up to 60", trying to make sure I had 18" for the bezel/monitor area and then I added whatever was left to make the machine hit somewhere around 60". I basically start with a template for the side panels and I build the rest as needed... I use 1/4" mdf for the back boards.
I have a vinyl cutter than I can load paper into and draw my designs so that's what I do, then I cut out my pattern, trim it, and tape it on 1/2 mdf and rough cut the first piece with a jigsaw then sand down smooth with a palm sander. I then use that original trace out two more side panels, the I rough cut those then clamp all three together and use a router to finish cut the two extra sides which are the two I will use in my build. I keep the original side as a template in case I want to build another. (So maybe a Mad Planets or a Ms Pacman are in my future... after a Pole Position and a Operation Wolf (with original gun)).
I rent a 1300 sq ft home with two kids and a wife and the garage also houses my race car so building these things does two things for me... it has helped me learn how to do some wood working I was afraid to try and allows me to build something kid friend (perfect height for my 8 year old to stand and play and I'm 5' 7" so not much bending for me, a stool will be perfect)
Here's some WIP of my Galaga.... I took a picture of the bottom of the cabinet and the speaker panel that has my pocket holes with screws... I use a mileswood brand pocket hole jig and screws, 1" coarse screws.