The aqua lock part of the accessories seems to be a bit of gimmick to me. I have a 7mm Aqua Lock fullsuit that I wear with Oceanic gloves, an Aqualung 5mm hooded vest and DeepSee booties. The minimal water transfer using these pieces is similar to what I experienced when using actual aqua lock pieces. If the Henderson accessories fit me as accurately as the others, I might be able to discern a difference that I'm otherwise unable to.
Either way, I'm quite happy with the fullsuit, though I did have to trim around the zipper on mine slightly as it kept catching near the top.
I'm 6'1", 170lbs, athletic build (negatively buoyant in fresh water), 32" waist, 34" inseam, 15" neck, 32" arm, 40" chest. The Medium Tall fits me near perfectly, though it has a slight gap around my midsection. Wearing a 5mm vest takes up the slack completely.
What you're comfortable in is a personal preference and even that can vary. When we were in Little Cayman (~79 avg) a few months ago, my wife mostly wore a 5mm fullsuit and I was usually in a rash guard and boardshorts. We just got back from Belize (~82 avg), where she typically wore a 0.5mm skin and I was comfortable in a 3/2mm fullsuit. In Monterey (~52 avg), I can dive wet comfortably in a 7mm with a 5mm vest, or a 5mm with a heated shirt, though my preference is to dive dry at that temperature.