Hi R0CKnU,
Welcome to the Mattress Forum! 
The “soft” Talalay latex used by Savvy Rest is 100% NR from Radium and that would be in the 15-20 ILD range. This is Cradle to Cradle GOLD certified Talalay.
The Nature’s Embrace – Tempo mattress that you described uses 100% NR GOLS-certified Dunlop latex. The “medium” layer is 85 kgM3, or about 5.3 lb. density, which is usually in the mid-30s for ILD. The "firm layer is 95kgM3, or about 5.92 Lb. density, which could be in the mid-40s for ILD.
When attempting to compare what you tried in person to an online manufacturer’s offering, be sure to let them know exactly what you tried in-store, as these manufacturers should be familiar with the products of many of these brands and they would be best at comparing what they are able to offer you to what you liked in-store. The site members listed in post #21 here are all very experienced and knowledgeable and specialize in providing the type of help and guidance on the phone that can help you make good choices and comparisons. There are a wide range of latex mattresses and toppers included in the choices there and I believe that all of them compete well with the best in the industry in terms of their quality, value, service, and transparency.
I’m wondering if you have the two Savvy Rest toppers confused. The Vitality uses a stretch covering that is quite flexible, and the Harmony uses the stiffer cotton ticking quilted with wool and a backing (which does soften a bit over time but is still a stiffer covering). You are correct that the covering certainly does make a difference in the overall feel of the product, especially the covering in the uppermost layers of any mattress. When ordering any topper, you can request that you desire a covering that has more of a “stretch-knit feel”, as opposed to a “starchy/boardy” feel.
While the quality of the componentry in the mattress you tested is certainly quite high, as you mentioned it certainly falls into a bit of a “higher-end” price range, and you may be able to find some options online that provide a bit better value for the same or very similar products. You can make “value” comparisons between mattresses based on suitability (how well you will sleep), durability (how long you will sleep well) which in this case would be comparable since they are all latex mattresses, along with all the other parts (including pricing) of your personal value equation that are most important to you. The link to the site members I listed earlier would be a good place to consider starting with your online comparisons.
I’ll be interested in learning about what you decide to do.
Phoenix