Low ring Med ring ?

Ok new question is I recently mounted Dot rails on my .22 and .45 I'm about to purchase rings for them to mount the dots onto the rails and I don't have access to the rings in my area so I have to mail order them. So I'm thinking that I want rings that hold the dots as close to the barrel as possible yes ? and will a "low" ring have enough clearance for a 30mm dot ? or should I purchase a "med" ring ? these would  be weaver style rings.

Yo are right that you want the rings as low as possible. That being said it is hard to find reasonably priced low rings in 30mm size. I ended up with Weaver mediums.

the best 30mm  rings ive found is the weaver low model # 49121 they sell on ebay for about 22.00 these mount the dot solid and low

Aimpoint makes a set of 30 mm rings that are lower than the Weaver rings.  
Use them on my wadgun.
http://www.amazon.com/AimPoint-30mm-Riflescope-Black-12229/dp/B003YF0VFC

those look just like weaver quad locks.

Thanks for the help and the links I think I'm all set.