Below is a link to a paper written in 2012 by an artist and PhD chemist, regarding varnishing of oil paintings. His name is Chuck Mauldin and his bio is on his website but it’s also in the paper. To summarize, citing a thesis by a (I believe) Dutch chemist and his own work and observation over a 15 year period (he admits it’s not all necessarily scientific) his conclusion is that the 6-12 month rule is unnecessary and that there is no reason to wait any longer than 3 weeks. He states that as soon as the paint is dry and firm to the touch, go ahead and varnish. I know you can do this with Gamvar, but his conclusion is 3 weeks is fine for all varnishes. In fact, apparently Gamvar was pretty new when he published this paper, as he mentions it briefly as a new product.
I just came across this when I was looking at his art work. He’s very good by the way. He’s also got some pretty good chops as a chemist, with 56 patents registered. https://userfiles.faso.us/40607/8721.pdf