Stearman are cool
OK I thought I'd chime in.
I have a Stearman built from the royal kit ( pic in my gallery)
I had a real bad tail-heavy condition on my first flight. Mostly because I did believe the plans, anyway I got that fixed with about 2 lbs. of lead in the cowl.
I have a ys 120 + this 2 lbs. of lead and mine still only weights 12 lbs. How did your turn out 14.5 -15 lbs?
The incidences' on the plane are critical to smooth flight. Mine has +4 deg in the top & bottom wings, +3 deg in the tail and with the engine at 0-0 deg as per the plans.
I wouldn’t deviate from the plans if I were you
I don’t know if this is going to help or add to the confusion. but these extreme incidences make the plane fly in a scale like manner ( tail high). The 120 is way more power than I need. I was think of going to a 91 fs. When I fly at full throttle the plane doesn’t seam happy and really it doesn’t look scale either. I fly mostly between ¼ and ½ throttle.
lastly on the n-struts, I used the streamline aluminum tubing
After quite a bit of jigging and cutting I got them set up perfectly.
Then the angle connection was made using line for fishing rods and epoxy. the tubes slide over a hard wood piece and are held in place with 4-40 bolts
Good luck with your plane