Ever try using a mini pump to inflate a tire. Its not fun, but it definatly works. I've used all three methods (CO2, full size, mini) and have come to the conlcusion that all three are not fun. So realistically, a mini pump is no worse than anything else. The size comes as a trade off for speed. I've yet to rip off a valve. The 85 psi will work, trust me, the moment its full enough to ride, you will stop pumping. I'm not a commuter yet, but I can see an added advantage of a mini pump being you can cary it into work with you and prevent it from getting stolen.
scott