If you're in the US, Stako bottles haven't been approved for use yet by the DOT so you can't get hold of one yet. And even if you did, it couldn't be filled. There's some great info on reg recharge times here: http://www.pbnation.com/showthread.php?t=836422 . According to those results, crossfire beats the nearest competition by 4 ms with Centerflag in second.
u could try gizmos they have a wide range of air tanks that u can buy and they have there own make of guerilla air tanks that u can customize to better suite ur gun