Hi rmz100987,
When you can’t test a mattress in person then a more detailed conversation with a knowledgeable and experienced online retailer/manufacturer will be your best source of guidance because they will know more about their own mattresses than anyone else (see mattress firmness/comfort levels in post #2 here).
The Ten includes a 3" layer of their new specialty polyfoam material while the Five includes a 2" layer. Both have a 1.8 lb polyfoam support core underneath. Based on conversations with them they would have a very similar firmness and “feel” for most people although for some people that are in higher weight ranges a thinner mattress may feel firmer than a thicker mattress.
The only way to really know how any mattress will feel for you (regardless of how it feels for anyone else) will be based on your own personal testing or sleeping experience but they have a great return policy so if your conversation with them gives you enough confidence that the mattress would be a suitable choice for you in terms of PPP (Posture and alignment, Pressure relief, and Personal preferences) then there is little risk in trying it because if it doesn’t work out as well as you hoped for then they have a great refund policy and you would be free to choose a different mattress.
Phoenix