Well, your schedule looks pretty good! Seems like he is getting bf'd enough throughout the day to me. If you are feeling your bf supply is low, you might want to offer the breast a couple more times during the day, like before solids just to try to up your supply.
If you do the df, I would suggest doing it with a bottle of formula or pumped milk instead of taking him out and bf'ing him. That way you know he is getting some milk and it will take that question out of your mind. I would do the df no sooner than 10:30 or right before you go to bed if it's later than that. I tried to elevate my ds head a little with a small pillow, so he didn't choke. I could do it without waking him up though, so do it only if you think it will not wake him. then if he wakes during the night, try pat/sh, sucking on a paci back to sleep or pu/pd. If he acts starving, then feed him, but he really shouldn't be hungry after a bottle at 10:30.
Let me know how it goes...I have a 2.5 year old hanging on me right now, so I don't know if I'm making sense or not...sorry!