Objective lens is too big for a decent depth of field. No bigger than a 40 or 44mm lens would be best.
You might be better with a variable mag, something like a 3-12 so that you have a chance to find the mag that suits you.
I would suggest you go to the HFT comp at York on the 14th and have a look through a few scopes. If you're not sure about asking a few people, get Wayne to grab hold of a few of us.
Different people will give you differing advice on what mag to use, and what ret to use for your aim points. It comes down to what is going to suit you however.