Synergistic Effect....Probably Not. However, Forskolin can be a great ingredient....so there very well could be additional benefits, although I'm not positive to what extent. If your diet is good....and moneys not an issue, why not?
As for pump spray, I personally dose it one time a day due to convinience and kids. However, you can dose it twice a day....just make sure to space it 8hrs apart. 45 minutes prior to exercise or after a shower (completely dry) are great times. After a shower your pores will be opened up, allowing great absorbtion.
Hope this helps!