Arthur,
Great score on the buckets! You couldn't buy better in a 5 gallon size.
Are you doing an indoor grow only or will these plants make the move to outside?
I ask as there will be different considerations for both. Lighting, humidity, cover, etc.
Rockporter is spot on with her comments other than the specific MG product you have.
Shake 'N Feed is a continuous feed so it could be used as a fert strip. (but 2 Tbsp doesn't seem like enough)
I would add that the soluble fert is OK in a SWC, just not as a fertilizer strip. You can use soluble and feed on whatever schedule you choose. If you use soluble as a fert strip, you run the risk of dissolving it all at once and that would not be good.
Coir vs peat - Not having used coir I have no first hand experience with it and I am reluctant to tell you to ditch it as you already have it.
We are all limited in some respects by what products we have, what we can get, and what we can afford.
I am sure people are using it without issue, but as Rockporter mentioned, the general consensus seems to be peat is better for a SWC/SIP application. I think you can get results from coir, but need to hit on the right mix for wicking and aeration.
Wicking - size matters in relationship to the container size and in relation to media used.
Forgive me if you have already been through the material below, but there is a lot of great information and first hand experience in it so it would be worth it to spend some time.
Global Buckets
http://www.globalbuckets.org/
Raybos Earthtainer and Inntainer Threads and guides
http://earthtainer.tomatofest.com/pd...tion-Guide.pdf
http://earthtainer.tomatofest.com/pd...tion-Guide.pdf
http://tomatoville.com/showthread.php?t=16694
http://tomatoville.com/showthread.php?t=20459
Wicking alternatives
http://greenroofgrowers.blogspot.com/search?q=wicking
http://www.insideurbangreen.org/2010...gardencom.html
Potting mix for 5 gal buckets (Rockporter's mix inside)
http://tomatoville.com/showthread.php?t=22688
Another recent link here on Coir vs Peat
http://www.tomatoville.com/showthread.php?p=338881
Utah State paper on Coir vs Peat
http://scienceofnature.info/media/articles/cocovspeat.pdf