Ys110 with 15x10 and 15%coolpower I get 8800-9000 rpm.

Reinforce the firewall and landing gear plate by using balsa block or triangular balsa. Just use epoxy or elmers glue. If you dont have triangular or blocks what I do is use 2-3mm balsa sheet, stack them up with your adhesive to get to around 9-10mm and cut it to your desired shape and refinforce the corners of the landing ply and the firewall.