RE: Octogonal Barrels and Scope Mounts???
T/C for years carried a mount that would clear the hammer on the rifle. CVA also did. But I think through just lack of interest (because traditional shooters did not use scope and a lot of states out lawed them at the time) the sale of these items was so poor that they kind of faded away. There are some out there floating around.
What make of Hawkins carbine do you have as the distance on the flats and the hole patterns change from brand to brand. I have a few sets of scope plates that you can then add a weaver base to, and then your set of rings. I can find them and see if they might help you.. if you give me the make of the Hawkins.
I never tried those gorilla grips. I will have to call T/C some time and talk to them about those things.