Hi Alohabob,
The Ironman 3.2 (and 3.3) models both have memory foam under the latex while the 3.1 doesn’t which is probably why they felt so much softer to you.
Believe it or not … their claims have some science behind it and their descriptions are not all hype. If you call the outlet in Kelowna I mentioned he could probably fill you in on the layering of each of the models but they do use good quality materials in their mattresses. There’s even a mattress protector that uses Celliant and there’s a couple of articles here and here that talk about how it works and its benefits.
There are some other polyfoam choices listed in the DIY thread in post #4 here as well in case you want to do some shopping around. Both of the ones you listed are very high quality HR foam but they certainly aren’t inexpensive either. You would probably be fine with a little lower density in the base foam and the same firmness level if you wanted to reduce the cost. The comfort layers are the “weak link” where the quality of the materials is especially important.
Your choice of toppers are also fairly firm and if I had to guess, especially in combination with the firmness of your core, your mattress would probably be firmer than the Ironman 3.1.
I’m not sure what you’re seeing but both of the layers look fine to me. Of course you may be more comfortable with foamorder … and I do think highly of Alan … but I don’t see an issue in the picture in the post.
The biggest challenge won’t be getting good quality materials … there are lots of good sources … but getting the layering right so you are comfortable sleeping on it.
The good news though that if you do get it right then there’s nothing quite like the feeling that goes with sleeping on a mattress that you designed yourself 
Phoenix