Hi pdforta,
Welcome to the Mattress Forum! 
Unfortunately, there is no way that I’d be able to predict what comfort might be “enough” for you, as it’s not possible to make specific suggestions or recommendations for either a mattress, manufacturers/retailers, or combinations of materials or components because the first “rule” of mattress shopping is to always remember that you are the only one that can feel what you feel on a mattress and there are too many unknowns, variables, and personal preferences involved that are unique to each person to use a formula or for anyone to be able to predict or make a specific suggestion or recommendation about which mattress or combination of materials and components or which type of mattress would be the best “match” for you in terms of “comfort”, firmness, or PPP (Posture and alignment, Pressure relief, and your own Personal preferences) or how a mattress will “feel” to you or compare to another mattress based on specs (either yours or a mattress), sleeping positions, health conditions, or “theory at a distance” that can possibly be more reliable than your own careful testing (hopefully using the testing guidelines in step 4 of the tutorial) or your own personal sleeping experience (see mattress firmness/comfort levels in post #2 here).
The mattress in question uses 3 cm of reflex polyfoam beneath the innerspring unit, and on top of the spring unit is another 2 cm of reflex polyfoam, and then the 5 cm of 65 kg Dunlop latex. 65 kg density would generally be considered a more plush latex. You’d also want to learn of the density (and ILD if available) of the reflex polyfoam layers.
That mattress uses the same 65 kg Dunlop, and the same configuration of reflex polyfoam, but the spring unit uses a thinner 16.5 gauge (versus the 16 gauge in the Harmony 1000), so you’d want to speak directly with the manufacturer for their rating of these two models and how they would rate one versus the other to comfort.
In this model the Talalay is rated at a 60 kg density, so this would have a softer comfort. At a similar ILD, Dunlop will generally have a firmer feel than Talalay, due to the higher compression modulus of Dunlop versus Talalay.
A side sleeper generally prefers a bit more conforming surface comfort, but again I can’t predict what you personally may prefer. When you can’t test a mattress in person then the most reliable source of guidance is always a more detailed phone conversation with a knowledgeable and experienced retailer or manufacturer that has your best interests at heart and who can help “talk you through” the specifics of their mattresses and the properties and “feel” of the materials they are using (fast or slow response, resilience, firmness etc.) and the options they have available that may be the best “match” for you based on the information you provide them, any local testing you have done or mattresses you have slept on and liked or other mattresses you are considering that they are familiar with, and the “averages” of other customers that are similar to you. They will know more about “matching” their specific mattress designs, options, and firmness levels to different body types, sleeping positions, and preferences (or to other mattresses that they are familiar with) than anyone else.
Their detailed knowledge of their mattresses and how they fit with different body types and sleeping positions along with your feedback from local testing, a customer base of many people that they can use as reference points, and any exchange, return, or any options they have available to customize a mattress after a purchase can help lower the risk of an online purchase. These online retailers or manufacturers can also be a good “value reference” for local purchases to make sure that if you are paying a “premium” for a local purchase (in exchange for the kind of “in person” guidance, service, and value that comes with dealing with a local retailer that can help you make more “accurate” choices that you have tested in person) is not too high.
I hope that information helps.
Phoenix