So how was it on fuel for the first 20 hours ?
I have about 60 hours on it in a month now

Break in, shake down and a trip added them up quickly.
Fuel Use - Last week did about 145 miles motoring with the sailing is subtracted out. It worked out to about 30 hours of motoring and used 10 gallons.
14.5MPG and 1/3 gph.
About 4 hours were wide open, most around 5 mph half throttle, and a few hours slow timing bridges/locks. The 90 averaged about 1gph @ 6mph 2k rpm. Opened up it drained 6 gal in 45 min at about 3mpg. I did the same stretch of ICW last spring, but 40 miles less, and used a little over 20 gal, so am happy with the fuel use. I shouldn’t need to take jerry cans on trips anymore.
I picked up a pump to drain ballast and tried it out in the canals. Took about 30 minutes to pump out, the bow came up about 4” but made no difference in speed or RPM.
I have used 6 props on it now. Basically neither 4 blade worked, they both slipped and ventilated trying to get over 6.5mph when the boat is plowing. The 3 blades are predictable, the 10” pitch stops at 7mph/4k and the 7” pitch 8mph/5300rpm. The 10 pitch reaches 6mph at 2500 vs 3000 rpm so I swapped back to it for the second half of the trip since I was in no hurry.
Overall it took some mental adjustment that I couldn’t just hit the throttle when I was getting tired of motoring down the ICW. I am looking at it as a 1 speed boat …sailing whether there is wind or not…and that works for me. It took longer days with it on the same trip, but resulted in more stops and had a more relaxed trip overall. I was able to practice maneuvering it in a lot of situations through locks, bridges & stops last week. As long as you don’t come in too hot its nice and relaxed with good control. I took some pride when next to the other transients and delivery crews doing the same maneuvers (in larger boats of course) with a less fuss than them.
I am glad I had the 90 and enjoyed it thoroughly. Would I buy it over or trade for a new 90, absolutely,

will I trade back up, probably not.

The little motor does what I like to do.