HELP with bodywork

Hey guys, i no that spraying some epoxy primer would be the better way to go, but i really just cant go that option as i dont have any place to do it....the bottom line is that i have to work with what i have....Im only going to spray the high build primer on the car just so that i can block it and see where im at....once thats all done the body guy is going to spray a coat of sealer over....the painter actually even told me to do it this way (buying spray bomb primer for blocking), and since im on a tight budget and can only do what im able to do, i have to go this route....Im sure some of you guys have gone this route before, so how did it turn out for those of you who did? This is my first time doing bodywork, and its on a daily driver, so its not going to be perfect and i know that already, but im still trying to do as good a job as i can within the limits set on me

As for the other parts of my plan, what steps do you guys recommend i take in sandpaper grit? Is 80, 120 then primer then blocking with 220, 320, 400 wet enough? This is what im a little more concerned about since everyone seems to have their own little preferences...Anyways guys thanks for the advice so far and please if you have any more lend it over

Thanks again
Matthew