I think you have some valid points about selling SBD to keep price of Steem up whenever it seems to be undervalued.

How does the blockchain create rewards for each approach? I know that it generates new SP for the SP side at both 50/50 and PowerUP100. I believe that it also generates new SBD on 50/50, but not on PowerUP100. All the curation rewards I have seen are paid in SP.

There is an ongoing demand for SBD to feed into bidding bots. What do the bidding bots do with the SBD? In most cases I think it is paid out as ROI to the investors that delegated their SP to the bidding bots. Then what happens? SBD feeds into bidding bots, SBD is sold for SP to delegate to bidding bots (compound returns). If the feed their SBD into bidding bots, it's a closed system in three steps. If they sell for SP to reinvest and get compound growth, it's the same as taking SBD instead of SP, but two steps removed (and supports bidding bot economy in the intermediate steps).

If we think of Steem as a closed system, then whether your method or mine is better depends on whether we would want to support the bidding bot system. At that point it comes down to philosophical rather than mathematical differences. Are bidding bots good for Steem, should people use them, etc.

But Steem is not a closed system, and new money can be invested into it (either through buying Steem, buying SBD, or buying SP directly). If I post at 50/50 I again have the choices of selling SBD for Steem and propping up Steem immediately or passing it through bidding bots (which still props up steem, but at 2 steps remove). Except that now bidding bot investors have an option of selling their SBD, which would lower the SBD/Steem ratio, also propping up Steem.

If I post at PowerUp100, the logic changes. If I don't use bidding bots, I am completely removed from the SBD/Steem exchange rate (except for whether I decide to invest new money via Steem or SBD). In this case, your position is the stronger position, as I should be taking SBD and selling it for Steem to support the Steem price. But if I do use bidding bots, I am supporting the price of Steem either way... except that I will run out of SBD because I do not have a ready supply from posting rewards. To continue using bots without powering down, I am required to continue buying new SBD- so my new money comes into SBD directly, or comes in via Steem, is sold for SBD (depressing Steem price) which goes to bots, then to bot investors, then into SP for reinvestment (supporting Steem price)... much more circular and market neutral across my own buying/selling/powerup except that I have to keep bringing new money into the system.

So again it depends philosophically on whether bidding bots are good for Steem. If you don't use bidding bots or think they are bad, you should post at 50/50 as it will provide more support for Steem price (regardless of whether you bring new money in or not. Obviously continual new investment will provide even more support for Steem price).
But if you do use bidding bots (and I use them extensively; this is no secret), then posting at PowerUp100 shows a stronger commitment to Steem (and provides more price support) because it mandates new investment to keep up bidding bot use, rather than making new investment optional.
And anybody that actively uses bidding bots should be proactively investing into Steem to show that their actions align with a belief that bidding bots are not actually harmful to Steem.

This ran long, which means I might reuse portions of it in a later post. Don't waste good. I hope that you were able to follow all the logic, as it does get into some second and third order effects. I would love to hear your perspective.

x-post from my response to your comments on my post, so that your readers have equal chance to respond and tear me to shreds for using so many bidding bots. (: