First - light - stack without any -racetam

I am wary of huperzine, I think it would lead to downregulation of the cholinergic system, unless there is evidence to say otherwise. Galantamine would be a better option, but is often only available via prescription, and you'd only want to be taking a tiny amount if you lack relevant disease states.

I recommend checking out bacopa and rhodiola for a natural, mild cognitive boost.

Coffee would also be preferred over caffeine, as coffee contains beneficial phytonutrients in it that make it a health-promoting form of caffeine.
Seafood (even canned) would be preferred over omega 3s, as they contain health-promoting dipeptides and are more suredly health-promoting than fish oil.

Alpha GPC is a good choice, you might like to add Uridine as they are a good combo. Theanine is always good and cheap too.

Thank you Adam, your advice is really welcome !

I've heard contrasting opinions on both bacopa and rhodiola. I thought that alpha gpc + 1 ingredient (like uridine, as you said) would be sufficient for my purpose.

Any opinion about dosage ?

Thanks again!