What is worse, to have the blower speed higher and the temp set at 75 or the blower speed lower with the temp set on 60-65? I am in San Antonio and since the temps have been in the 90's my mileage has gone from 46 to 40

Unquestionably: It is worse to have the blower speed lower and the temp set to the 60's.

Also, see here for more detail:

http://www.greenhybrid.com/discuss/172793-post2.html

Cheers;

MSantos