Hi Headlightslui,
I switched your post to a new topic of its own.
The first suggestion I would make would be to talk with Dreamfoam on the phone about which of these would likely be the best choice for your son (see mattress firmness/comfort levels in post #2 here). IMO … there are too many unknowns and variables involved to use email as a way to choose a mattress (see post #2 here from earlier today). They will know more than anyone about which of their options will most likely be the best “match” for different body types and sleeping styles based on “averages” and the more information you can provide them the better you will help them to help you make the best possible choice.
Dreamfoam makes mattresses that use high quality materials for their budget range and have great value but I would also be aware that with your son’s higher weight that it may also be worth considering higher density materials unless budget is the most important criteria because this would also increase the cost of a mattress. There are some foam density guidelines in post #4 here that may be helpful.
Post #13 here also has more information about the most important parts of a successful mattress purchase that may be helpful as well.
Finally … I don’t know if you are looking at their Amazon listings or their Dreamfoam site but if you order from Dreamfoam then you have the benefit of having a 45 day comfort guarantee and they also currently have a 10% discount on their mattresses (see their facebook page here).
Phoenix