Need prop information for my 23 albie special please

[dock total]

I have a new to the family albie special with some beat up props. I was wondering what size anybody else was running as I'm going to replace these anyway. I have b3 props a 570a 5.7 with a 290 duo prop . I'm cruising at 22 mph at 2800 rpm and getting 2.75 mpg in the bay. Any help would be appreciated

[Old Blue]

I'm still on the old 280 but there's at least one of the 23 footers around who are running the duo prop.
How much horsepower is that motor?

[dock total]

The engine puts out 260 hp