Hey danielle_schuster.
Welcome to our Mattress Forum. 
First of all, major props to you for doing such thorough research. Itâs clear youâve put a ton of thought into your needs and preferences, and that really sets you up for success in this process.
Charleston Mattress is definitely worth a look, especially since youâre local. Theyâve got a solid reputation, and being able to try something in person (especially with your very specific needs) can be a huge help.
Youâre absolutely right that finding the right balance between your very different temperature needs is tricky but not impossible! Latex and springs are great for breathability and cooling, so leaning that way makes sense for your partner. But for you, layering will definitely be key. Think of the mattress as the âneutral baseâ (to support both of you), and then use your own cozy top layers (like wool, flannel sheets, or even a heated mattress pad or foot warmer just on your side) to keep your extremities warm without overheating your partner. No need to suffer in silence with 10 blankets if there are smarter ways to stay toasty! Thereâs more about the mattress microclimate that may interest you here (itâs Phoenixâs reply).
On the hypermobility side, youâre already on the right track thinking about comfort layer thickness and latex type. The one youâre thinking of is Talalay latex (the âTâ one!) and yes, blended Talalay in the high teens for ILD is a solid starting point. It gives you a responsive but pressure-relieving surface thatâs not too âdeadâ feeling. Just be mindful that 4 inches might feel amazing for pressure relief but could need dialing in to avoid too much sink or instability, especially with your joint sensitivity.
Support layer-wise, either a firm Dunlop base or a quality spring system can work reinforced pocket coils are great for motion isolation and spine alignment, and there are some excellent ones out there that balance durability with responsiveness. I wouldnât say you need to go for the most expensive coil units unless youâre seeing meaningful upgrades in zoning, edge support, or coil count sometimes the difference is in the details.
Your pillow setup is also super relevant - stacking two (especially with something like a Purple on top) can sometimes throw off alignment depending on your shoulder width and mattress feel, so just be open to tweaking that after you find a mattress that works better for your bodies.
It sounds like both of you have a lot of sensitivities (understandably!), so just be patient with the process finding the right setup is definitely a bit of a journey, but it is doable.
NikkiTMU