Hi Kelly. You've gotten some very good advice already here! I recently went through this with my DD (now 7.5 months).
I think Natasha has a good point with A times. At 6 months we pushed DD to 2.5 hours in the am and between 2-3 in the pm (depending on length and quality of first nap). Of course you'll need to extend A times slowly so you don't get Zander too overtired - I find stroller walks, a bit of TV, cuddles, stories, etc help with this. We extended 15 minutes every 3-4 days and are now at about 2.75-3 before am nap and 3-3.25 before pm nap.
Perhaps you could try the following:
E 7am BF
8:30 am Solids
S 9:30-11
E 11:30 am BF (unless he's crying for feed you don't need to stick with strict 4 hour feeds once you are on solids)
12:45/1 Solids
S 2-3:30
E 3:30 BF
5pm Solids
E 6:30 pm BF
S - 7pm Bedtime
This way you can also try to cut out the catnap. If you can get Zander to get in two good naps during the day (or at least one long one) and until at least 3 or 3:30 pm, you may be able to start dropping the catnap. You may have days/weeks where this goes back and forth - some days with catnap, some days without...
HTH. Let us know what you think.