Hmmm...I sort of understand the logic about putting a product in and wrapping the tail to 'seal' it in, so to speak...although I suspect that the issue with the product and wrapping the tail are two different pieces of advice put together. In general, I've found that wrapping tails -does- help them grow and protect them...regardless of product.
Do you have issues keeping in tail wraps otherwise? Or is it just with the MTG? If it's just with the MTG then I think you need to alter your method of wrapping because it really shouldn't matter what product you use.
I hope that helps! =-)