Regardless of how you mount the firewall, for added comfort, pin the firewall. I put 3 in each side and 4 on the bottom. I doubt that it will ever pull away from the fuse.... unless I change the engine to a turbine or something!!
Also, read back about the tail being a bit heavy and how you can counter it. Look at getting longer engine mounts to put the engine out as far as it will go. Every little bit helps. I think I can balance it ok now - even with a Pete Model's carbon fibre spinner on the front end. It arrives tomorrow or on Monday.
Spar