Hi loraxc,
While other people’s comments about the knowledge and service of a particular business can certainly be very helpful … I would be very cautious about about using other people’s experiences or reviews on a mattress (either positive or negative) as a reliable source of information or guidance about how you will feel on the same mattress or how suitable or how durable a mattress may be for you and in many if not most cases they can be more misleading than helpful because any mattress that would be a perfect choice for one person or even a larger group of people may be completely unsuitable for someone else to sleep on and reviews in general certainly won’t tell you much if anything about the quality, durability, or “value” of a mattress for any particular person (see post #13 here).
While your own careful testing or personal experience is the most reliable way to know whether any mattress is a good “match” for you in terms of comfort and PPP … 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 and firmness levels to different body types, sleeping positions, and preferences (or to other mattresses that they are familiar with) than anyone else.
Having said that … forum searches on Astoria and on Versailles (you can just click the links) will bring up more comments and feedback about both of them.
As you mentioned the support core on the Astoria is two sided and can be flipped to provide firmer or softer support and “feel”.
This would depend on the pocket depth of your sheets relative to your mattress. If the pocket depth is 2" or so more than the thickness of your mattress you should be fine.
This normally isn’t an issue for most people with a heavier topper (such as memory foam or latex) especially if you have a fitted mattress protector and sheets on top of them which also help to keep them in place (see here for example)
Phoenix