M.85... sounds like someone in the company should've done some trigonometry for you, to support the SOP. In the case that you've mentioned, you're 10 NM from the VOR/DME and you need to find a point that is 3 NM prior to the required final approach radial.
Therefore, arctan(3/10) = 16.7 degrees. Call it 17 degrees. Thus, you'll be 3 NM from the final approach track with a radial set up that is 17 degrees prior to the final approach radial. Surely someone in the company could translate that to the required radial for this approach at Tabba?
Finding a distance of 2 NM is achieved the same way :-
arctan(2/10) = 11.3 degrees. Call it 12 degrees and your lead radial for that position is 12 degrees prior to the final approach radial.
The Pans Ops forumula results in slightly different numbers :-
3 NM = 17.2 degrees
2 NM = 11.5 degrees
But it's all close enough for practical purposes. Maybe you can convey this to the folks who write your SOPs? In any event, I'd have thought that the company would've done this for you anyway, so that you'd know whether the lead radial for the turn is at 2 NM or 3 NM, or some other distance - a case of every little bit of information being helpful.
alf5071h... Spot on, as always. That's a good summary of the design requirements.
