So I guess you discovered that with the solenoid disconnected, your hot starts were better?
The best gasket material is called diaphragm material and has a very thin layer of fabric in the middle of the rubber outer layers. It will still be 1/32" thick. Hard to find but maybe McMaster has it. The fabric will not allow the rubber to "squeeze" out when compressed.
From the Pacific Fuel rebuild, my solenoid rod measured 1.890" from the metal base to the top of the rounded nut when the rod is bottomed out. I discovered that a 1.750 rod dimension will not engage the rack. so it seems it may only move the rack about 1/8"? Seems too little but that is what I got and maybe not totally accurate. Yes, the rod stroke is much longer, but it has to depress the spring loaded lever before contacting the rack. Let me know what initial measurement you came up with.