ok if your only problem is getting him down for naps then i would start to move towards 1 nap (slowly) as this is most likely the reason for the nap refusal.
you have 2 options for starting the transition, either keep the early nap and wake him up from it (so it is short) and go for a longer PM nap, or push the am nap back and let it be long and go for a short late catnap in the pm.
so the options would look like this for this age (aproximate)
6 awake
9:30-10 nap 1 (wake at 30 min)
1 or 1:30 -3:30 nap 2 (don't wake up from this one, let it be as long as he wants)
7 or 7:30 bedtime
or:
6 awake
10-11:30 nap 1
3:30 or 4-4:30 nap 2, wake after 30 min
7 or 7:30 bedtime
the option where you wake from the first nap is usually best when you are getting nap refusal because they will then take a second nap for you because you limited the first nap and they are tired. there is usually less nap refusal with this method.
you will continue to shorten the one nap as he gets older and when he can tolerate about 5 hours A time you can go for 1 nap. most bubs go to 1 nap between 12-18 mo
hth