I found the firewall already had 5mm blind nuts installed that fit the EME-35 perfectly. Will also work with a DLE-30. The stand offs for the EME-35 use a 5mm cap screw thru the firewall to the stand-off. I wanted to use the 5mm blind nuts that where already installed so I install 5mm bolts into the stand-offs and cut the head of the bolt off. I then installed them to the firewall and I had to use some 3/8 plywood to extend the engine out to get the 6.5"(165mm) need for the prop hub distance. You can see in the last pic there is down trust configured into the firewall. Here are some pics that show how I did this