would i be able to do this? hopefully pic explains all

You are effectively putting them in series so the charger should see 4s1p. Your diagram says autodetect 1-3 cells. I'm assuming that should say 1-4? Thats how I wire to charge my nimh 7.2 on my SB979.

it indeed does say 1-3 cell auto detect and has a seperate light for 4s charging, this is why i had a concern, not sure how to set up charge rate on 4s because for some reason it isn't auto detect,but the max charge rate for the charger is 3.0a so i think it should be fine even if the highest charge rate is selected since they are 3200 mah. One more question though, since im still using the x646/3 how many amps do you think the motor is pulling? How do you measure this? Batteries are good for 64 amp constant discharge so i figured with only a 45 amp esc they should be more than enough battery, but i've been wrong before, next time i charge my batts i'll try the 4s configuration, it sucks waiting for both packs to charge seperatly. thought i'd ask on this one so i don't "humiliate myself" I know i should switch to a 442 or the 440/3 like everyone else but i love the hard launches with the x646/3 not to mention it handles a lot better than the stock prop. i dont see how my prop can be any worse the the cf48 some people are running. I really do hate the cavitation of the stock prop. Is the x442 still good for launching? is it easy to balance? the 646 was a pain in the arse to balance, most of this is off topic but whatever.