Restrainers and base fog

Wile doing reversals, chasing that maximum density seems always limited by base fog.

My question is if I add a restrainer to the developer to reduce the base fog, does it also reduce my maximum density? Is there any magic bullet?

Do you use thiocyanate or thiosulfate in the first developer to clean up the highlights?

I do use thiosulphate, but that is not what I am asking. My question is for the developer itself. I am after the maximum silver development without (or at least minimal) useless base fog.

Here are my steps for introducing a new film to the process....

1) Process unexposed film to bench maximum development without base fog.
2) Expose and process without hypo sample images with successive iso exposure (25,50,100,......) This will reveal a base iso
3) Expose and process with hypo (varying amounts) until exposure is acceptable.

So my question is pegged to step one. If I ad a restrainer, will this also lower the max density as well as the fog?

I guess I just answered it myself. I made a saturated solution of borax and added 2ml to a 150 ml of dektol 1:1 @ 15 mins (drum) with tmy. I got a 3 stop increase without any base fog. For reference, I got base fog at 6 mins without the borax. This must boost my DR and am looking forward to some real tests.