Using the old fashioned hardwood beam mounts is usually pretty much a thing of the past what with all the good plastic and metal mounts currently availble. Reinforce the firewall and use a plastic or metal mount held on with machine screws and blind nuts. If anything happens in an argument with runway you can remove the mount and replace it much more easily than a beam mount. If the beam mount gets cracked or oil soaked you will have to disassemble the entire front part of your fuselage to replace it. The removable mount may cause some damage to the firewall in a crash but that will be easier to repair than removing and replacing a beam mount.