A Q35 should fly a 16lb 1/4 DR1 great. You sure the Quadra/muffler will fit upright? You will probably have to set the firewall back a couple of inches? Cooling? just those two holes and a little around prop driver for air in? Prop, 19/6 or 8 or 20/6. Scale would be 24", too big for 35. I have a G26 mag with 18x6 prop in mine and have about 3lbs lead if I remember correctly. Good luck with your project, have you thought about color yet?