Download the Rega arc protractor from vinylengine and you'll have all you need to align a cartridge on that arm.http://www.vinylengine.com/ve_downloads/index.php?rega_arc_baerwald.pdf
(You'll have to register at vinylengine before you can download.)
Did your dealer throw in the Michell VTA adjuster? You need some kind of VTA adjustment as the 10x5 is taller than Rega carts. The dealer may have already done this, but you may want to experiment with adjusting the level.
I had a 10x5 on an RB300 mounted on my Gyro and thought it was a very enjoyable combination (until I KO'd the cantilever.)