you should post pictures of your cab, that would help.
I had an operation wolf conversion, placed a 21inch CRT VGA screen similar to what you are describing. The problem was to find out "how" to put it in there... there was no way I could redo what they had originally done and still have room in the cab; computer screen often have long tubes. I ended up making a shelf. here's some pictures, for inspiration.
slanted back didn't work:

ended up making a shelf and putting the monitor in there. Easy, really:

I am currently making a japanese cabaret conversion to MAME; it used to have a VGA arcade CRT. I tried to put a 19" CRT in there, there's no way it fits - I have a similar issue, but no way up front to fix it:

I might be able to put a 19" arcade CRT in there, but the one I have is in unknown state, and fitting it in there seems very tricky; altough I think once in there it would fit perfectly.
For that one, I'm going LCD; seems the best option. Plus, it is WAY lighter. but it doesn't look as good for retro game play - if you want that old 80s look, LCDs aren't great.
Really, its not just a matter of monitor, but there's personal tastes in there, plus the cab itself. Do your CRT fit in there to begin with???