#402 front and #55rear, or
#20A front and #45 rear.
The FN Comercial action came with a modified low swing safety,IIRC.
The #402 is an extension base and allows mounting of shorter scopes and is approx 0.125" taller than the #20A/45 arrangement. You can also use the #45/46, but I recommend the 402/55 with the Leupold 2x-7x, as that is what I have on one of my Interarms MkX's. The rear objective of the Leupold requires slightly higher rings to allow the bolt handle to clear the rear objective with the MkX and similar bolts. MidsouthShootersSupply.com has a very good chart for the Weaver bases. Other distributers/vendors don't list/show that Weaver Chart anymore.
Brownell's sells (or did) the Beuller low swing saftey for the Military M98's. I believe the Commercial FN Mauser had the safety on the side attached to the trigger assembly as does the Interarms/Parker Hale actions.