I guess you found a good middle way to test everything out. 😄

To test the increasing ratio in the background with an unlimited supply seems like a solid idea. I'm still concerned, but there will be no harm of at least trying. The peg is at least 1:1 so no way of dropping below that. Good thing!

Regarding the old "invest" feature:

To disable any share of profit for those deposits (especially after @tipU disabled already it once) is the right thing to do.

For the auto-reinvest: The first option is basically no auto-reinvest, because the deposits will no longer bear any share of profits.
(Or is the payout just a deposit without a share of the profit?)

So I would go with the second and third option. Make it a choice, like SBD, Steem or SBD and Steem. In this case, SP or token.
If that isn't possible to code, I would plain and simple go with #2, just the tokens. They want to reinvest, they get token, which bear a share of the rewards and @tipU is able to use the Steem as SP for those tokens. Which is actually a really functioning way to put some real investment into @tipU.

I'm pretty sure, we will see a great @tipU token and a new shiny website. 👍