If you have the original tube, you can remove the yoke and use a tube from a 25" TV. I swapped one in my Daytona USA and it looks great. A 25" tube that fits a 25" k7000 is also the same size from my experience (you just need to use the yoke from the original MS8-26 setup).
These RCA output line converters are inexpensive and work well to connect a CPS1 multi mono audio to a stereo wired cabinet.
I soldered a mini plug to the CPS1 multi adapter card JAMMA pin audio out pins. Then I connected one of these output line converters by installing a plug on it so that it...
My CPS2 multi LCD screen was damaged and I ended up buying a replacement on Amazon and soldered it in. It works just fine. The dimensions are slightly different so I had to modify the 3D printed case I had for it slightly, but it running well. Four replacement screens were included for about $13...
Also you might consider an Atari Centipede cabaret and a cabinet to JAMMA adapter. It has a 19" vertical monitor and you can get a repro blank control panel for it which you could make into whatever layout you like.
Or there are people who CNC Atari cabaret cabinets so you could make one...
I have used one of those flyback. I don't have a lot of hours on it, but it did worked well so far. It needs a voltage pot to be adjusted as initially your image will appear too large. The seller was helpful and chatted with me.
There is a pot on the chassis, called V Lin or vertical linearity (or named similar) that might help you out, it is on the far right end of the row of pots on the chassis.
I also used a repro flyback and adjusting the pot allowed for the size to fit correctly. I've not run it a lot of hours but it seemed very solid whenever it has been turned on.
Just thought I'd check back if a mono/stereo addon for playing all the mono games in a stereo wired cab is in the works yet. I realize I could otherwise wire something up.