Azrael's golden rule #67 - Always pin boys!

I use GS as well but I don't know how much support it gives?
As for the greenstuff/superglue mix I always find that pinning and using superglue gel to fix then when dry gs to fill cracks and potentially add support works for me.
I would be worried about unknown chemical reactions taking place between the supreglue and greenstuff. But that being said, there may be none

Then pop the model under a hot lamp/hairdryer to help the GS set faster.