Wow...I get to answer my own question for a change!
At the time of my posting, I had written to Kevin Steele at Retroblast with the same question--he kindly replied with this informative message:
"Rob,
First off, thanks for the kind words - I'm glad the site's been helpful!
As the questions:
1. You don't need the video amp - the Betson (like the D9200) is designed to
accept a standard PC video signal (31-38Khz). The signal from even an
ordinary PC video card will display bright and sharp (at least, at 640x480
or 800x600!)
2. I have had no problems with the Betson - it's definitely been a "plug and
forget" part of the arcade machine the last few months. Now that I have the
new version of the ArcadeVGA card (based on the ATI 9200), it's even better:
sharper picture and good 3D accelleration for games such as Mutant Storm.
(I'm planning on updating my ArcadeVGA review shortly to reflect the changes
in the new version of the card).
As far as any other suggestions: just one - be sure and download
"RefreshForce" and use it to remove the 1024x768 resolution (and higher)
from Windows, as well as force all video modes to a 60Hz refresh rate.
http://www.pagehosting.co.uk/rf/I forgot to this time while reinstalling everything on my cab, and
accidently selected 1024x768 mode. The monitor immediately put up a "signal
out of range" message and I couldn't see the desktop to get back to a
supported resolution. I ended up plugging another monitor into the PC just
to reboot and force things back to a supported resolution. Even safe mode
wouldn't work...
Good luck with the cab!
Kevin"
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Figured his input could be valuable for others too...