New into this world and getting an AstroCity with HD7770. A lot of questions

[Kernelchagi]

Hello! Im getting a Sega Astrocity in the next month. The cabinet is already restorated and fully working so my idea was to connect it to a PC that i have here and that im not ussing anymore.
The pc is an intel i5 2500k with an Sapphire HD7770. I know it is a little overkill but is what i have. Im getting little confuse with so much information so im writing here to check if i got it everything right.
First i have to buy a JammaSD, then i have to format the computer and install windows 7 with the calamity drivers to get 15khz signal. Then install groovymame, romset etc and the last the frontend.
My questions are:
1.Ussing a 7770 wich has 2 DVI ports, where should i connect the vga cable? I guess i need an VGA-DVI adaptor.
2. The computer has not PS/2. Can i use an usb adaptor?
3. Will the PC fit inside the cabinet as it is an standard size pc?
4. Will the chassis of the monitor suffer from the resolution change of groovymame and from getting higher resolution from the computer before starting windows?
5. I have a good experience with rgbpi and the community and is super simple to make it work and i think it will be the same with the jamma connector. Is it really worth it to make all this way to make the cabinet work with the pc? Im willing to do because there are games i like and they cannot run under the raspberry but its looking so complex that im getting demoralized ;(
Thanks!