First time I've seen a tractor fan on an Enforce, most are pushers. Go a few post up and there are three pictures of a nacelle (Fan Housing) for the enforcer I'm building. this is for a pusher fan arrangement.

Your extra nose weight came more than likly from the pipe and support, that a looooong moment arm hanging out the back, and the further the weight is from the CofG the more weight it is going to take to balance it.

the ideal placement when doing a regular enging to DF conversion like this is for the engine to basically end up in the same place, I would say your engine fan assembly could come quite a bit forward. but hell, if it works fly it