(2019-08-07, 16:47)Magnus Forsberg Wrote: Is this colour mandatory to use on the top surface of trans sticker?
No, this is just to let trans stickers look nicer.
(2019-08-07, 16:47)Magnus Forsberg Wrote: Should we recycle all stickers with colour 16 on the top surface, and change them?
No, unless you give me a very good reason.
(2019-08-07, 16:47)Magnus Forsberg Wrote: Is it OK to use another colour than 16 in a sticker+part shortcut?
Well, I'm not a friend of sticker+part shortcut and don't have really an opinion on it but I would say NO.
w.
LEGO ergo sum