14" radius short scale setup specs?

[CPplaysBASS]

Hoping some current SX Ursa Short Scale (or similar) bass owners can help me out a bit.

I'm very comfortable doing setups on my own (long scale)basses.

I just got delivery of a SX Ursa Short Scale bass for my son. Considering the cost (and there are some obvious indications of it being an inexpensive bass), I'm quite happy with it, and so is my son. Neck pocket is a little sloppy, but the bass sustains incredibly and I'm pleasantly surprised by the tone.

My understanding is the neck radius is 14". I currently have the relief at .013 and the action is set at 8/64 (Ok ... 1/8!) at the 17th fret.

It's comfortable for ME to play, but I'd like to try at get the action down a little bit for the sake of my son.

Anything less that .013 relief and 8/64, even by a hair, results in unplayble E-string buzz. At those settings, however, it sounds great. The problem is my son doesn't have my hand strength and callouses. Ideally, I'd like to get the action to 6/64.

I know generally that on a long-scale bass, a flatter 14" radius would mean less relief and lower action is possible than the 9.25" radius I'm personally used to.

"Recommended" specs for a long scale 14" is typically .010 relief and 6/64 action. So three questions ...

1) what is the proper "recommended" relief for a 14" short scale neck? I expect the action needs to be higher for short scale but not sure about relief.

2) If you own a similar bass, what are your measurements?

3) Is a shim my likely solution?

Cheers!!