The second is a clamp on picatinney rail by Hi-lux, look at this link and scroll down to page 15, this looks pretty chincey and doesn't have good reviews
Burris makes weaver bases that mount to the Ruger. Then you can use burris signature zee rings with an offset insert kit to get the cant for long range. If you can find the discontinued signature rings that mount directly to the ruger that would be even better.