I almost did buy an arcade VGA, but I didn't like that I would have to use a legacy card. I wanted to be able to use a more modern card so that I could still enjoy games from later years as well as emulate more powerful systems, so I downloaded a hacked version of AMD drivers called CRT EmuDriver that allowed me to output lower resolutions. With it, I was able to output 15khz 480i and 240p. To connect it to my Sony Trinitron, I use DVI-to-VGA dongle for my Radeon R7, then the VGA cable goes to a VGA-to-Component transcoder box, and finally to my Trinitron's YPbPr inputs. Since even games on the same console platform can use varying resolutions, I am using super resolutions to compensate for the change of horizontal resolution different games may have. Using a super resolution also gives me the ability to adjust the width without introducing visible scaling artifacts. I use real console hardware and a Canon T3i on a stable tripod zoomed in to tweak and adjust the picture settings of the emulators I use phosphor-to-phosphor to match what the respective consoles output to a CRT. My goal is that when you play on an emulator on my CRT, it is a 1:1 match. In my SNES's case, the size of each phosphor won't match exactly what the original console outputs because I have the Model 1 SNES with the SHVC motherboard (which I prefer over any other SNES console revision for it's dedicated Sony soundchip) and it's RGB output has a slight blur to it, but RetroArch still comes REALLY close. I attached picture comparisons so you can see for yourself =)
SNES Model 1 SHVC-CPU-01 > RGB Scart to YPbPr transcoder > Component switchbox > CRT
RetroArch with BSNES Balanced core via Radeon R7 > VGA to YPbPr transcoder > Component switchbox > CRT
The color of the SNES is slightly different than what BSNES outputs, which is kind of puzzling because BSNES is supposed to be 100% accurate. It could be that I have to adjust the pots in my SCART-to-YPbPr transcoder to match the colors BSNES outputs, or it could be another variable. It also looks like the emulator is just slightly tilted, which I'll have to look more into as well. I know that for the Chrono Trigger comparison shot, my tripod shifted a bit because my dog ran through the room and my tripod is on carpet, so keep that in mind when looking at that comparison shot =p
Chrono Trigger Retroarch
Chrono Trigger SNES
Donkey Kong RetroArch
Donkey Kong SNES
SM All-Stars RetroArch
SM All-Stars SNES
I also adjusted the picture to compensate for the overscan CRTs are well known for. In the SNES's case, the picture stops on the right side of the screen before it hits the end of the electron beam's field on my CRT. I simply adjusted the horizontal viewport in RetroArch.
RetroArch side shot
SNES side shot
It's been a lot of fun trying to get the output of various emulators on RetroArch to match their console counterparts. So far I have worked on the NES, SNES, Genesis, N64, Game Boy Advance and the Super Game Boy 2. I've also worked on the Game Gear as well but I didn't go very analytical with that one since I don't have a way to output the original Game Gear on a CRT, so that was more of a guessing game. I will say that playing GBA games on a CRT with RetroArch is PHENOMENALLY better than playing on the Gamecube's GB Player. My Gamecube is hooked up via S-video which isn't much worse than YPbPr when playing on a CRT, but the color muckiness of the GB Player, along with the fact that it outputs 480i, makes playing it on RetroArch much more enjoyable.