Hi IronMan,
When you can’t test a mattress in person then a more detailed conversation with the retailer or manufacturer is the most effective way to make a comfort choice (see mattress firmness/comfort levels in post #2 here).
The tri comfort also has the option of exchanging layers after a purchase so you can change both the comfort and support of your mattress if your actual sleeping experience indicates that you need it.
I wouldn’t make it any more complicated than this either.
Phoenix