It's now several hours since you posted, so I presume whatever sales meeting is going on is now over. That means that now you can be by yourselves and think about things in a less-pressured environment.
IMHO - if you bought something, you should immediately rescind. My thinking is simple - you're in a binary choice situation. You can proceed with the modified ownership, or you can rescind. But the difference is that you have only a limited time within which you can rescind, but you can always come back and buy again if you decide that is truly what you want to do.
So you have little downside for rescinding. But there's a big downside to not rescinding, because you might find yourself saddled with a contract that you can no longer exit.
************
If you submit rescission paperwork, they will probably try to contact you to talk you out of rescinding. They will tell you about benefits and perks you will be losing if you cancel.
Don't let that sway you. Just keep in mind that if the deal is such a good deal, if you take more time to think about it you should only become more convinced of the wisdom of the purchase.
And here's a critical point, if they truly believe the product was as good as what they presented, they should have no problem with you taking time to do research. Because if the offer is that good, then if you take time to think about then, you should be even more sold on the value of the deal. The only reason for them to be reticent about having you take time to step away and give it more thought is because they're afraid that with more examination, you will realize the deal isn't as good as it seemed to be during the presentation.
************
[added comment]
My standard response if they push me for needing more time is that before deciding I need to construct a cash flow analysis and calculate an internal rate of return on investment.