I'd also consider waiting until you drive it a while before you think about gears. Mine has a 373, every time I got out on the road I'd be in the right lane, engine spinning and traffic passing me, pissed me off. You should have enough torque to get the thing moving fast with a 323-342 ratio and still not rev the heck out of it above 50mph. But as oneinch says, it depends on how you want to drive it. 373 to 410s are great for drag racing but suck if you drive to the track, 100 miles with 410s would irritate me but I use mine for more than driving around town. A 355 would be a good compromise, I was going for that until I changed the transmission.

Man that attachment looks good, I'm going to pop a cool one.