If the P120 is sat on packers as the original manual then it does climb slightly under full power, When we raised the elevator servo mounting plate after the first 6 kits, the turbine can go on the rails, or even mounted above the rails (the JC mount on the top side of the rails model on its wheels, or under rails looking through wing opening)
But- even with the spacers it did not "pitch" up and climb, it would just climb slowly at full power. I only ever used full power for loops etc so it never bothered me and I did not notice it.

Something odd for sure

Dw