Completed drilling nut plate holes and other mounting holes in the firewall and contactor doubler. Rough fit parts and realized I should make the fuel feedthrough doubler even taller than needed to support the starter contactor mounting bracket so I can countersink the doubler instead of the firewall. Fabricated new fuel feedthrough doubler and match drilled it to the firewall. All that remains is to drill the large hole for the bulkhead fitting after I decide the pilot hole is in the right spot. Inspected the aircraft spruce and Airline Hydraulics shipments and the three mesh screens I purchased from Amazon. Wrote Aircraft Specialty asking about where the 8 brake hoses should be located. Many of them were similar lengths. Got a prompt response from Tom. Added the information to the maintenance manual. Drilled a 5/16" hole in a copper bar that will go between the two contactors. Need to finish up the final mounting before I drill the second hole. Considered several options on where to locate the ANL fuse and how to mount it and connect it to the contactors. Reviewed the schematic and wire size tables to see if I really needed the 6 AWG wire and decided I should keep it that size. Thought about installation order of the contactors and copper bars and decided I might want to change the mounting bolts to socket head cap screws. Created new symbol for the 24021 starter contactor by marking up the S702-1 B&C contactor to remove the internal diode. Updated the schematic with the new symbol.