I think you are doing everything right and have a sweet running engine. What carb are you using ? What prop hub ?I'm running a 52" prop (52/42) on my 1835 dual port. I see about 3,150rpm on takeoff. And, a little more than 3,300 WOT straight and level at SL. I can typically see 750fpm on climb out at 90kts.
I don't baby that engine. Tooling around the local area, I tend to keep it up around 3,200 RPM. And, I regularly do aerobatics. It has over 400hrs on it. And, it still purrs along. The builder swears it'll go to 1,000 and then some. I believe him.
This biggest concern I have is the heads. Those 8mm studs seem to have grown just the tiniest bit every time I check. I retorque the heads and change the oil every 25hrs. I'm sure if I wasn't doing this, the 3-4 head would have already failed by now. But, compression is still very good, the CHTs stay below 400, and it doesn't burn any oil. So, I must be living right.
I just recently flew it 400 miles round trip to Van's to pick up a small part for my RV-8 build. It purred like a kitten all the way. At 3100rpm and leaned out cruising at 4,500'msl, it burned slightly less than 3gph.
At the rpm's you are cruising at, it's really a toss-up between single or dual port heads. I would lean towards the single port at that rpm just because the lack of cracking problems in the single port heads compared to the dual port heads. But most of the cracking problems of the dual port heads are the result of running the heads to hot.