making urahara faster.

iz4n4minok4mi

As was said, senbon + t1 through supports is basically a no go. The difference in speed especially after the buff is just ridiculously big. Even with shinso gin who is really fast you could have trouble if you were using some fast assaulters like white ichi, isshin etc.
Your best bet currently is either stack one strong aoe assaulter if you have any (white ichi, res. ulquiora, yamamoto) and make him T1 and then the rest of the assaulters can have t1 through kisuke OR you need to change your zanpakuto. If you rely on your assaulters mainly, then zangetsu would be the ideal choice as it is quite affordable and it gives some nice bonus to basically everyone. If you have strong supports then muramasa instead. Both of them costs +- the same as they are basically identical just one buff supports more and the other assaulters + muramasa has higher reiatsu bonus.
Katen or tensa would be ideal of course as they give nice bonuses to everyone including vanguard but because of that their price is simply somewhere else compared to zangetsu and muramasa.