VPI Scoutmaster Tonearms

You can upgrade to a VPI Classic 2 or VPI Classic 3 arm (I did) but it will involve some minor drilling (note: the VPI Classic 3 tonearm provides on-the-fly VTA adjustment).

As for other "non-VPI' arms, you will have to drill through the plinth for the tonearm wiring unless you get something like a Tri-Planar VII Ultimate tonearm ($5,700 US).

The thing to remember with some of the VPI turntables, like the Scoutmaster, is that the "acrylic-like" material that VPI uses, gets sticky when it heats up. It sticks onto the drill bit, making it easy to mess up.

Upgrading to a 10" arm on a Scoutmaster would require drilling?

No drilling required....the arm mounts on the surface which requires installing 3 (I think) screws....very easily done. VPI will send you a metal guide for precision installation. The only caveat is that the screws go in straight and not at an angle...again...easily done

If you want to use same mounting holes as your VPI 9 inch, you can look for a used 10.5i (pre Classic) arm that has the adjustable dog leg bearing mount. All you will need to do is rotate the dog leg which holds the bearing to achieve the right S2P distance.