I'd be agreeing with brisvr4, instead of messing around with the expense of bulkhead fittings, I will/would be replicating the factory setup in 3/8 steel pipe and flaring the ends. I read a article about it ages ago. You remove factory pipe through the top of cradle and peen the hole larger to accept the 3/8 pipe. Your hole should be funnel shaped. Position pipe and solder in position. All good.
I haven't investigated it yet, but that is my plan. I have already adapted the top of tank piping to accept the proton fuel lines. But a wiring and piping upgrade is in the future.
Can always double flare the pipes if you think a single flare isn't enough. Brake lines must be double flared.
