I just have the Mini Vac, and I do keep it unscrewed a bit to let the ink flow - that might seem odd, but it's of no consequence most of the time. I love this pen and appreciate it the longer I've owned it (about a year).
I've taken it to Europe (it did not leak on the plane), tight it before take off.
Forgot to tighten it down on a drive up to Mammoth Lakes and it did leak, so you do have to be mindful of altitude changes - but I LOVE the fantastic ink capacity, the overall balance in my hand, and it's among my favorite smooth writing pens.
Honestly, I doubt you could go wrong either way.