I guess you fellas got me on the higher pressure argument, but I think you're majoring on a minor point. You're right about the higher boiling point, steam pocket mitigation, and promoting better coolant to metal contact is all good stuff you get with a crossflow, but they're all secondary to the improved cooling efficiency you get with increased surface area.

If you can fit a crossflow get one for sure, as long as it's at least as big or bigger than a down flow you can squeeze in there. Ofcourse I'm talking surface area of the tubes, not physical dimensions.