So judging from this data is the best course of action to use these plates up till ~lvl 6 then use gold the rest of the way?
No upgrade them all the way with build tokens. I doubt this will be the only event that gives them. Use gold on Osman and lands. Edit just put them all to level 6 and go back and max them later I suppose.
You all do you. What one player deems "worth" will vary from another's. You can get those 900b abyss ugs for "free," or farm lv1's for gold, whatever. Do what fits your play style. Is there a mathematically best solution? Yes, there usually is. I haven't done the calculations, but they can be done. But that answer won't make everyone happy with their own use. Follow your heart, and/or wallet.
sounds like trouble for other devices ;/... I couldn't use a single one either for diff reasons tho :|
A mod commented elsewhere that to use tokens, you need to update to the most recent version. That fixed it for several people.
Looks like they changed Abyss level 5 -> level 6 upgrade to be just as efficient as the previous upgrade, by making it also 40 tokens rather than 50.