Sorry for the hassle, but I still don't have enough info - if you want you can e-mail me, or we can continue.
So, with a POG GSC transmission, the wallet is scanning the available coins, and finding 298.436615MM coin age available.
Then it says, I need 238.749292MM for this transaction of coin age (80% of the age).
Then it tries to create a set containing this amount and fails to find that much age in an amount of 5.73MM.
So lets try this (those 3 pastes above didnt have enough coin age selected).
Please re-paste 'exec getabnweight 238749292 1' and 'exec createabn 238749292' and lets see where those fail now?
No problem. Alas, I think I went one step "too far" now for this kind of troubleshooting. I selected that 4.5 M chunk in coin control and did "exec bankroll 20 200000" and this actually worked (which is quite logical, since this requires no coin age). So now my wallet is pretty much spent regarding coin age.
Next couple of days and weeks are pretty busy for me. I think I'll just let it sit for a couple of days and see where this is leading. Then I'll try again next week. If it still doesn't work, I'll get back on that.
Thanks for your efforts.