Macker, I have to say I started out with a pair of neo's, 3mm, but found them to be BLOODY hot during our summers here above the 45th. So I switched to a pair of "Breathers" when, on a rather long hike through the woods, first day of a 3 day excursion, I tore a significant hole in the right foot of my neo's! Thats right no repair kit or super gooo. I made the best of casting from the shore, and made some bone chilling crossing's, brrrrrrrrrr!
So for your first pair, breathers would be my choice! And you can adjust the clothing under to your own comfort zone.
Oh, the neo's? They act as my back-up pair now, stashed in the back of the pick-up, just in case
And I remain..........dry