Foaming is a PITA. Air bubbles cause lean runs, even as stated, stoping the engine. Any direct contact of tank to wood will transfer the vibration. Free foam is "findable" from electronic stores.
As a rule the softer the foam the better it isolates vibration. Foam can become fuel soaked and compacted loosing it's vibration reducing quality. Bagging the foam in sandwich bags isolates it from fuel and keeps it soft.
So use the foam, your engine will thank you![8D]