If anybody has a lightweight or a TRR and can't find a base that fits, NightForce makes a 20moa and Talley makes both a 0 and a 20 moa. If you go online to Talley's website you will not find them but if you put the following part numbers in the search box, it will bring them up and you can order them. For the lightweight and ultra lightweight's I would email Talley and verify the fit, they are quick to respond. They verified that these would fit my .308 TRR.
Talley -
P00252706 flat rail
P0M252706 20moa rail