which rail to buy (?)

I have a 10/22 Target model and would like some more 'adjustment' potential for my scope mounting (i.e. closer/further from my eye). It's my first venture into the 10/22 world and I think I've seen some info posted about something tricky regarding the top of the receiver relative to mounting a picatinny rail. Would appreciate any info on a recommended make and model p-rail . THANKS, John

And the answer is: Weigand #R1022RECP