Can I substitute Ener-G Egg Replacer with Orgran No Egg? I'm interested in hearing any success (or woeful failure) stories on the behavioural differences between these two products. I've only found Orgran No Egg available for sale in my city, so my fingers are crossed.

In particular, I am curious to pursue this macaron recipe.

Unfortunately I don't quite have the budget to justify learning this by trial and error! Any input is greatly appreciated.
Based on their ingredients they should be pretty similar (Orgran: Potato starch, Tapioca flour, Calcium carbonate, Citric acid, vegetable gum (stabiliser): Methylcellulose vs. Ener-G: Potato Starch, tapioca starch flour, leavening (calcium lactate, calcium carbonate, citric acid), sodium carboxymethylcellulose, methylcellulose). 

Do you have any bulk food co-ops / health stores in your area? Sometimes they sell Ener-G or similar products in bulk, that way you can just buy the few tablespoons that you need and try it out before investing in the whole box.