By dangerous I should have stated that two rich clicks lowers the take off rpm substantially and the airplane with a .50 is not or barely is at flying speed on grass.

You have a 10% larger engine and I tend to believe that an 11 x 7p would be correct. However with your .55 the 10 x 7p will probably turn 14,000 plus on the ground. If take off is not sluggish it will probably go faster in the air. You picked a better engine size. I have observed substantial heating on a long ground taxi and often a sag on take off which is another reason for a larger engine.

Bill