'Glycerinergics' has only one result on Google - this article. Even if we assume that they mean it in the same way as we talk about GABAergic or dopaminergic drugs the definition they have stated is fundamentally incorrect. Glycerinergic drugs would be those that bind to any of the same sites that the endogenous molecule glycine binds to - not necessarily just NMDAr sites, this is an over simplification. Further more, to say that NMDA receptors are inherently 'stimulatory' is frankly ridiculous. Ligands can be either agonists or antagonists at a given binding site - examples of non-excitatory NMDAr binding drugs would be the arylcyclohexamine family (PCP, Ketamine, PCE etc) and Dizocilpine (MK-801). Finally, 'overall signalling is increased' is almost laughable. 'Signalling' through which neurotransmitters? In what manner? How is 'overall' measured?
While I may not have an absolutely perfect understanding of psychopharmacology, I do know enough not to trust this article - particularly when it is taking about drugs with very little history of human use.
If you are considering using the drugs in this article, it might be advisable to question why. Just because a compound is new, does not mean it is going to be better or the effects more desirable than it's predecessor(s). Of course it is possible that it could be, but it seems likely that in reality you are simply exposing yourself to unnecessary health risks for minimal reward. Would it really be so bad to use Piracetam for a couple of years while the phenyl derivative's action in humans is not well documented? Consider your health and the potential gains carefully and make a rational decision.