Well, it took this long, but I finally got a Halo AR and J2 base layer set and then finally got to dive them yesterday.
Thanks again
@Tracy for the info. I got a 2XL, as you suggested, and it is fine. MAYBE a 2XL Short would fit me, but I have no regrets about getting the 2XL.
I've been using the Seaskin Tech Base as my base layer for a few years and it does an awesome job (and it is very inexpensive for what it is). It is very reliable at keeping me feeling dry even when I know I've been sweating inside my suit.
For colder dives, I have been using the Seaskin Tech base with Waterproof MeshTec 3D shirt and leggings over it. That works great for dives that are too cold for my Merino mid layer. In short, my skin stays feeling dry, and the MeshTec stuff preserves a decent air gap for insulation.
Yesterday, I dived with the J2 and Halo AR setup. I've only done one dive with it, but I will be using it every time, going forward, until I find some reason not to.
The biggest thing about it that impressed me yesterday was that I got in the water with my drysuit zipper not closed all the way. I got it TO the zipper dock, but not that last 1/2" or so ONTO the dock. It was a shore dive. I walked down the stairs, turned around and lay back in the water and pushed off. My suit immediately started taking on 55(-ish) degree surface water, but it still took me a minute or so to get back to the stairs and stand up. I took on a decent amount of water.
I was pretty sure I had not gotten the zip shut and I was right. As I was standing up and fixing it, I could feel all the water running down inside my suit into my feet.
But, I proceeded with the dive. Once the water inside warmed up, I was very impressed to note that not only did I not feel cold, I didn't even feel wet! The Halo AR absorbed all that water and held it, so that I didn't feel like I had wet anything against my skin.
And all that was after I had been suited up, zip (mostly) closed for an hour before we got in, as I was helping a former student get her new BP/W set up and fitted correctly. Something we should have done before I suited up, but hindsight is 20/20. The point is that I was sweating like a fiend for an hour inside my drysuit before we even got in. Then I flooded the suit. And I still felt warm and dry during the dive.
I've had 4E Arctic (shirt and leggings) in the past. I currently have a Seaskin 150 undersuit, a Seaskin 250 undersuit, and the MeshTec 3D shirt and leggings.
The Halo AR felt (in the one short dive) like it was somewhere between the Seaskin 150 and 250. I only ever wore the 250 once. It was too warm when I was diving deep wrecks in Lake Erie. I wore the 150 the next day and was chilly, but preferred it to how warm and also bulky the 250 felt.
The Halo felt like it will be warmer than the Seaskin 150 while also being slightly less bulky.
Similar bulk to the 4E Arctic, but probably warmer.
Warmer than the MeshTec 3D.
Bonus: I was diving my rEvo (with 2 x 3L steel tanks), in a trilam drysuit, with the Halo AR, in fresh water, and I used no lead at all and it seemed as though my weighting was perfect. We did the dive mostly swimming between 10 and 20 feet deep the whole time and I was not "too light". I was on the edge, but still, happy that the Halo AR did not add enough bulk to make me have to add lead.