Thanks for the input guys. Since I'm just starting out, I really appreciate the guidance!
RigglePLC - I realize its a bit late, but the big reason for it is because sometimes we still have a bit of snow on the ground by then and things are still quite soggy, as well as spring cleanups sometimes go into late May. I will do some more research on spring soil temps in the area as well.
Smallaxe - Since in theory one blanket app should take care of most weeds along with proper maintenance, how might I go about setting that up on a proposal? If I "quote" for blanket apps for both fall and spring, I feel like my bids will be considerably higher than others. Any suggestions?