The Tac-A1 base is meant to match the height of their chassis rail. And it’s epoxied on too, or they used to be. Would not remove it.
I think this is in the wrong forum. That said, get the Spuhr mount. It matches the Euro aesthetics exactly and should work more than fine.
It has 27 moa built in or something like that and will certainly get you there.
Also, in 6.5 CM a SB 5-25 would get you to 1km anyway even with a no moa base. But I would get the 10-20 Moa mount anyway.