Overall, roughtop treads have better traction on carpet than wedgetop, but teams have found that wedgetop has better traction than roughtop on surfaces such as polycarb.

Please note that while I haven't thoroughly tested this, roughtop worked beautifully for us on the bridge at both regionals we went to, and we balanced the same, sometimes better, than the wedgetop tread users, so I think the difference is negligible.

Also note that wedgetop tread needs to be replaced much more often than roughtop tread.

I have no idea about the rubbing alcohol thing, but honestly the two treads are grippy enough. If you really want more grip, try blue nitrile tread. It can be found at McMaster. One of the grippiest things out there, and can go through seasons without loosing its effect.