As has been said, German tan is close enough to brain tan to look and feel like the real deal and is far less costly. Brain tan is expensive for a reason, it is intensive labor and not many people do it, or do it well for that matter. I brain tan a couple hundred skins a year and most of the time the sell like crazy, some times not, but usually have a difficult time keepig up with the demand. If you can swap out the skins you have for german tan that'd be great, if not you can still make your shirt and do it well, smoking it will not change the texture of the leather but will change the color and smell. Good luck with it and let us know how it goes.