Metal Gear Solid V: The Phantom Pain Message Board  

I've been using the trainer to add GMP and recently started to develop the golden items and hit an error: "Could Not Develop due to insufficient resources/GMP in online inventory".
Example I tried to develop a golden item worth > 11mil it doesn't work BUT a lesser value item at 7mil, also golden, works!? All these times I have 25mil online GMP (full) and 5mil offline GMP. Is this normal?

Definitely normal. Local and Online GMP are two different, but connected pools.

Local GMP is slowly synced and siphoned into online GMP. I do not know how frequently, but enough that you should be able to develop some of the cheaper items at the onset and later on in the game... Anything.

This issue of course is that there's nothing you can do to speed up development time as far as I'm aware. It would probably take years to unlock it all. Especially with the cap of 4 items max allowed to be developed concurrently.