Thad: You cannot roll doubles on the first roll of a game....

Thad: Sorry, that wasnt very helpful

Anyway, here are the accepted opening moves
http://www.bkgm.com/openings.html

Czuch Czuckers: Ok, well, I suppose you're right. My opponent won the opening roll, then I rolled the double 3s. I suppose what I am really wondering is is it better strategy to pull your stones out of your opponent's home with a good double roll early in the game, or use the double to establish blocks of your own in/near your own home?

Thad: I kind of lean towards blocking rather than a quick run, but it also depends on the opening roll of your opponent as well, but again, I like the block move over the run.

Thad: double 3s should move 8-5(2) 6-3(2) probably. Possible 13-10(2) in some cases, particularly if you can hit an opponents piece.

grenv: My opponent opened the game with 6-1 and blocked his seven-point. I moved 24/21(2) and 13/10(2). It seemed a little more important to advance my back checkers with that seven-point blocked.

Thad: Yes indeed, advance the back checkers and move the 13-10 or 6-3 or 8-5.

However if you need a gammon my first suggestion might still be better. )

Thad: There is no general answer for that, it depends on the rolls. The general principle is that doubles being a great roll, you want to focus on offense. This is because the positions where both players anchor high are mostly about equal, while prime against prime positions are not.
But tactics often overrule that principle. 3-3 is one of the most difficult rolls. The 3 is not a great point, but making it unloads the stack on the 6. The 5 is great, but making it abandons the 8. The 10 is not great, but it unstacks the midpoint. The defensive 20 is great, but you would like to focus on attack.
After an opening 6-1, the value of advancing the back checkers goes up, so I like your move. At www.bgonline.org there are all rollouts for all second moves that are considered non-trivial, and 24/21(2) 13/10(2) indeed rates as the best move.