Nice to read that Hardline is fully operational. 1100 idle rpm seems a bit high, those 4 strokes usually run at 800-900 idle rpm. If when gearing forward you hear a loud clack, try lowering idle rpm a bit for smooth gearing.
That 9.9 is rated for 5000-6000 wot revs, so you're 1 K under. Are you going for 3 or 4 blade alum props ? Are both mentioned props 3 or 4 blade ones ? I'd say need at least a niner pitch, but that's only a starting point as will need to be water tested.
Ideal would be to water test that niner with current load without the need to buy it and check if ok or go tad less in pitch, say 8 ? In theory need to go 5 less pitches with 3 blade props to pull 1k wot revs higher., but in real world paractice just 2 at most 3 less pitch.
Happy Boating
