I normally start with 135 for 15, 225 for 8, then my heavy set with is with 315...Sometimes I'll drop set down to 225, which I normally fail between 18 and 23 reps (depending on the time I take between sets). I have heard that if you go pass 315 you are simply asking for a pec tear (pros use HGH which helps with this). I know a guy who was maxing out (385lbs) and his pec riped.
I'll give you an honest reply. I used to handle 315 for 8-10 every week. I occasionally would do 365 for 3-4 or a 405 for a single (couple times got 2), but one time was too much and on a set of 365 I was handling it really well but my pec tore anyway.
IMO, do dumbells first, incline & flat, then do your benches. 315 will seem very hard and you'll not need to test your ego.