Inexpensive arm for bedroom table- Linn, AQ etc?

I'm looking for a tonearm for a Merrill modified AR XB that I'll be using in my B system. It has a Linn armbaord and I'm looking for something that will fit without any modification.

I can't spend more than $250.

I'm borrowing a Linn Basik LV X for a couple weeks until I can get my own arm. The Basik is of course pretty mediocre. Would an Audioquest PT-6 be a lateral move from the Basik, or would it me an improvement? What else could I look for given the modest budget and Linn armboard? Alphason, Helius, Linn Akito/Akito2? How do any of these compare?

I'll be using MM carts- initially a Shure M97xE -and FWIW the AR has a number of Merrill mods: subplinth, acrylic platter and lead mat, bearing, outer plinth, BDRcones off the top of my head.

Any advice is appreciated!
I had an AR ES-1 and i first tried a Premier MMT, w/ aluminum board, and it was too much for the light suspension of the AR. I then tried a LVX/aluminum board and thought it was an excellent match, the Akito is the same arm with non removable headshell, should be an improvement over the LVX. The PT6 is heavy like the MMT. I would look for a lighter arm, maybe Grace 707, RB250,Mayware Formula 4, Hadcock,etc.
Will Rega fit without mods? IIRC, Linn mounts 211 pivot to spindle and a length of 229; Rega 222 and 237 long and ditto for Grace 707--couldn't find hole size for any of them but this didn't look like a proper match for a Linn armboard? Color me confused--oh my lovely analog....
It's pretty easy to make an armboard out of acrylic, then choose the arm you want.
Thanks for all the advice Jalanc. Unfortunately it's not my turntable, so modifying it at all is out of the question--gotta stick with what's there.

Any other thoughts on Linn-mount tonearms, friends?