I guess my first question is :
Are you cutting them up for "joy of ownership" (i.e. your aesthetics) or "hope of return" (i.e. cash to cash)?
(Full marks to Auspost, of course, as they have doubled the number of new issues punters have to buy, in one fell swoop, and put a planned flaw in there, to make it "virtually compulsory". Cartier watches all round, I'd suggest
First up, whilst you can go head over heels about the value of the GB 13p stamp, it wasn't noticed at the time of issue, there are only 10 mint and three used out there (and yet possibly "a hundred in books, never checked, yet!), so their rarity rides high on a very few "well heeled individuals".
That's not the case here.
Make no mistake, this is a modern (comparative) rarity you need to buy "at about face", if possible (and maybe trade a couple of sets, to pay for it all), but the gold rush will probably peak just after xmas, and prices return to more normal levels mid next year, when people know "what the available pool is, versus long term demand".
They might, after all, choose to reprint the book "without the error", giving purists "a third whole set of stamps to buy, as a lump"
What's the market? Well, there are the traditional whole yearbook collectors, there are the "on cover" collectors, that will want a set of each, but there are also the mint and used collectors, who will need sets as they were produced in a different format. Short term, and with stamp fever, that's a spike where we will see "some silly prices".
Those that act fast should make the most. I expect people to be "in and out" by end of Q1 next year, and for many, that might even be this year end. (Filleting yearbooks, for their caviar, can give you "free postage" for the whole of 2021!!).
Certainly, if I were buying and selling them, then things like the Sheriffs cover are going to be most desireable "across a wide range of customers" on an enduring basis. (As he notes - No one wants the lumpy $130 a pop, but a $30 subset is "an ideal xmas gift").
From our experiences of UK mini sheets, and traffic light gutter pairs, which both waxed and waned a bit over the duration, we can see that there is often a tidal wave of interest upfront, especially with modern media
Who would have thought AusPost could have everyone invested $130 ($260 / $390) in fixed value stamps by the end of 2020? Bravo
When sending out post at the moment, I'm actually burning up a load of old miniature sheets (that were once popular, but are now just "discount postage"). I've found that there is a sub-class of collector that wants these, not fully showing the whole sheet, but with "just sufficient margin, to show it came from a miniature sheet". Apparently, it fits their album layouts better.
London 1980 Miniature Sheets - Forty years on, still popular with collectors.
So, fill your boots, with whatever you can get....
If they rise, you'll do well, and if they don't rise, well, you can still trim them onto parcels and delight customers with highly collectable examples of "format 2, 2020".
But, other than your own needs, for your own enjoyment, cash in "at an appropriate moment", to bring the net cost of your holding to zero ... then you'll be happy, "whatever rollercoaster they ride".