Thanks for your reply!
Yes I do really want the upgrade and would pay without hesitation (but don‘t want to waste cash either...especially as I have 100K miles that need spending). My gut tells me to wait it out too.

My biggest learning with this booking is that economy-flex is the best option regarding unplanned upgrades.

What do you mean with „flight is wide open...all the way to H7“?
Does H bucket have a special inference for the class load?

And by way, no biting...promised!