I'm currently waiting on my 28" 308 bull barrel which I plan on topping w/ a 20-30moa base and sightron 10-50x60mm. While I wait I'm shopping for rings. What height will work? I have read med will work but I'd like to hear what everyone else thinks. BTW, this is going to be used for f/tr out to 1000yds. I am hoping to be shooting berger 215 or 230's, if I can find them.