I am getting ready to send my .30-06 rifle off to be rebarreled to a .25-06. I plan on using 110 - 120 grain bullets, and I was wondering if anyone had input on the following questions: 1) What barrel length would you recommend? I was planning on going with a 23" or 24" barrel. 2) What twist would you recommend? 3) There are options for 3,4,5 or 6 groove barrels. Not really sure what that means. Which would be the best of these? Thanks for your help!