First off, you'd be better off with 3/4 tubing, with those kinds of flow. I'd pick the cheaper of the two: you're already up there, where more just isn't worth it.
Unless of course, you're putting together a test bench, in which case you'd want the bigger one, just in case some crazy fool
puts together a very restrictive block that you can't test at the same flow rates as all the other ones.