Good point, I guess it runs something like this
For the past 12 months i've used the following with seemingly good results.
In previous years i've used the following with good effect so i'm happy adding them in
Creatine and Glutamine
This leaves the BCAAs, Vit D and Electrolytes as the more experimental stuff.
It probably should try them one at a time but given that I think the improvements from these three are going to total a few percent in terms of recovery over and above the other stuff I'm not sure how i'd determine how effective each one is on it's own within the progress i make over the next 5-6 weeks.
What I may do is take them all until the end of this training cycle and then try eliminating one at a time to see if there are any adverse effects from stopping.