Hi HighRiser,
Restava doesn’t list the density of their foams on the site so you would need to talk with them and find out the specifics of the Delano’s construction to make any meaningful comparisons based on the materials. They are completely transparent and will provide these for you on a phone call. NOTE: They are no longer a member here since a redesign of their mattresses and they may no longer be fully transparent about the materials in their mattresses … see this topic.
Outside of a comparison of the materials in each mattress … neither mattress has any obvious weak links and both have excellent return policies in case your own experience on the mattress is different from their description or comparison to the Rhapsody Breeze (mattress comparisons are somewhat subjective and a mattress that feels very similar to most people may not feel similar to all people).
Post #2 here may help with deciding which is best for you when you are down to final choices between “good and good” and there are no clear or obvious “winners” or “better/worse” outside of the objective, subjective, and intangible criteria that are most important to you.
Each state can enact their own legislation that would apply to that state. As far as the fire regulations go if a mattress passes the federal fire regulations it can be sold in CA. I’m not familiar with California laws but there are some being considered here regarding the use of chemical fire retardants and if there are separate laws for California regarding mattresses then they would apply to online sales as well.
Phoenix