Hi yuppicide,
Thanks for the update and your initial feedback … I appreciate it.
You were probably wise to listen to their advice and I would wait until you have slept on your mattress for a few weeks before considering making any changes because there will be a break in and adjustment period for any new mattress or sleeping system as the foam layers lose any of their “false firmness” and the cover stretches and loosens a little and your body gets used to a sleeping surface that is different from what it is used to (see post #3 here). This would typically be a few weeks but it can be shorter or longer depending on the specifics of the person and the mattress.
If you go much softer with your body weight it could have a detrimental effect on the durability and useful life of your mattress.
Phoenix