My boat weighs around 58,000 pounds when it's loaded. It's 61.5' LOA and has a LWL around 50'.
For what it's worth, here are my numbers:
800 RPM: idle, dead slow, one-third. With mine, at 800 rpm's I'm doing about 8.5kts. This is a bit below hull speed. I don't really have a no-wake speed unless I take it in and out of gear.
1000 RPM: no wake. 10.5kts. This is close to hull speed and a very comfortable "slow cruise" speed for when we're not in a hurry to get somewhere. .
1400-1600 RPM: slow, two-thirds (easy cruise). I almost never run at this rpm range because it's too inefficient for my boat.
1750 RPM: standard (normal cruise). This is 80% of WOT throttle and (depending on load--water/fuel, etc.) we're cruising around 22-24kts. We cruise at this rpm if we're heading somewhere and don't want to dawdle. The boat really likes this as a fast cruise speed. The Cats are humming and the boat rides and handles well.
2150 RPM: flank speed, wide-open throttle. I don't run at this rpm range because we're burning ~65gph. We're cruising right at 30.1-30.3kts. The boat really likes this speed. I really don't like the fuel consumption so we don't do it often.
Mike and Tina
Beachcomber 1995 Sea Ray 550 Sedan Bridge