Hi,

It sounds like your stock may be a bit low, certainly it's worth eliminating this possibility. There are commercial products to address this:
http://www.cabelas.com/product/Shoot...3Bcat104606280

But before spending any money, try padding the stock up with whatever you've got to hand - foam rubber, folded cloth or whatever, held on with a couple of elastic bands - start thin & work up to see if there's any improvement?

Also, you say "I found that moving back a bit gives a clearer view but with a bit less tolerance of lateral movement." I think that will be the correct eye relief for your rig.

Regards