Is there a know method to create "correct" presets ?
Basically once you understand how the CRT timings themselves work the preset values are self-explanatory, being the only GroovyMAME specific part the last 4 values that indicate the vertical resolution limits where each crt_range applies. So for instance, the pc_70_120 preset is defined as:
crt_range0 30000-70000, 100-130, 2.201, 0.275, 4.678, 0.063, 0.032, 0.633, 0, 0, 192, 320, 0, 0
crt_range1 30000-70000, 50-65, 2.201, 0.275, 4.678, 0.063, 0.032, 0.633, 0, 0, 400, 1024, 0, 0
Meaning that the timing values in crt_range0 apply to resolutions of 192 to 320 progressive lines, and the ones in crt_range1 apply to 400 to 1024 progressive lines. The two ending zeroes mean we won't allow interlaced modes for those ranges.
As you see crt_range0 only allows vertical frequencies from 100 to 130 Hz. Here's where the magic happens: all incoming frequencies will be "scaled" to fit that range, so 55 Hz will become 110 Hz, 60 Hz will be 120 Hz, etc.
As for crt_range1, no frequency scaling is performed, so resolutions starting from 400p will be calculated with their native refresh.
Regarding the values in the middle, those are the ones that define the CRT timings and its geometry as a result. I'm afraid there're no intellectual shortcuts to manage those but to understand how it works, although if you just need to move the picture a bit to the right or left I can help you with that.
What will be the advantages if I use a Radeon card with CRT emu driver and this projector ?
I thought that was implicit in my previous post. Simply, GM will be able to use any custom refresh rate that is required (e.g. R-type will be able to run at 110 Hz (55 Hz x 2) instead of 120 Hz).