FF and Naps

DS is 4 months and has been EFF since about 5 weeks. He's become a lot more aware of his surroundings and not exactly one to 'nap on the go'. I guess it's part of the 3-4 month dreaded sleep regression (more night wakings too). His naps are short 30-45 minutes. He usually has about 5 bottles a day (1 MOTN) every 3 hours or so. After each bottle (but not,immediately after) he is put down for a nap. But when it's only 30-45 minutes and he still seems tired after, there's no getting him down for another nap until after the NEXT feeding. By then he has reached overtired territory. With regards to this, I wish I still nursed because then I could possibly get him back to sleep this way. Of course I'm not going to offer another bottle until his next feeding time. Anyone else have this issue?? At some point naps either need to lengthen or he needs to go longer between feeds. I've tried giving him more ounces but his max seems to be 6.