With a number of relatively cheap DCHDMI converters out there for handling VGA-->HDMI, I'd suggest you to upgrade for an increased res and image quality
Tempting, but I have a fondness for the lightgun games, which can only be used on a CRT.
Anyway, I actually figured out the problem, a whole 20 years later!
I've been fiddling around with various booting solutions to correct NTSC 60Hz games which boot up in 50Hz on a PAL console (Ikaruga, Grandia II, Sega Rally 2, etc.). There's a long list of problem games which should be 60Hz but force themselves into 50Hz on PAL.
After a lot of trial and error, and discussion on the DC Talk forums, I discovered that the Code Breaker cheat disc fixes this. No other boot option seems to work, not even the 60Hz hacked Utopia disc, nor GameShark or ActionReplay, both of which purport to boot in NTSC mode.
Anyway, the problem with RAH isn't 50/60Hz, it's the display signal output.
But I tried Code Breaker anyway.
BAM! For the first time I was able to load the game in 60Hz with a clear picture over RGB SCART on a PAL console.
From what I can tell, Code Breaker does not reboot the system like other boot discs, since it skips the DC swirl and Sega splashcreen, and goes straight into a game's opening screen. So, laymen's guess here, it bypasses whatever boot-up discovery mode the system goes through to determine screen output.
Code Breaker fixes RAH1 and pretty much every single other problem game I threw at it. Apart from Coasterworks.
So, there's no need for you to attempt to fix any code.
But if anyone else has this problem, that's the quickest solution: Code Breaker.
I hope this helps.