Lets take it one by one.

A 14size prop will hit the ground on our rather bumpy field. Also, the landing gear is a bit short

Everytime I open the cowl (once every two weekends) to scrub the engine, I have to remove the needle and hence I have to adjust it on field everytime. So if it was possible to correct this that way, it would have already happened.

Not Likely the engine is overheating I scrub it clean with soap externally every second weekend. The clunk has not fallen off.

Am attaching the photo of the cowl to indicate openings

I have ordered a dubro tank and it will be here before the weekend. I will try to get it in this weekend and check

Basically what I am asking is, should the tank be mounted any other way and is this engine suitable for 3D?

Ameya