Hey everyone!

I'm building my 1st kit (4* 40) and everything is going well. However, I think I may be a little pickey when it comes to building this thing. For instance, with this kit, the engine mount has to be mounted to the firewall before it goes into the fuselage. I did this and am not happy with the way it turned out. The way I have it, the engine mount is about a 1/16 to 3/32 of an inch tilted to the right. Also, when mounted, the engine would be about an 1/8 of an inch below the thrust line that I had to draw on the firewall. I was thinking of making a new firewall out of 2 pieces of 1/8 ply epoxied together (like the plans say) and using a great planes adjustable engine mount instead of the 2 piece one provided by sig. Is this nessasary? Would the plane be o.k with the way I have it? Does the manufacturer build in room for "mistakes"? My feeling is that if I'm spending all of this time building this thing, I want it to fly right, not like a brick. Anyway, am I being too pickey? Should I just say the heck with it and see what happens? Or should I just go with my gut, take the extra time, and redo the firewall and engine mount? The problem is, that I'll probably find other things that I think aren't right and want to redo them too! When do I say "it's good enough"? Thanks