I know perfectly this hard dilemna of B&G or colors tattoo... As I never find a solution, I just more or less divided my body in 2 parts: B&G on one half and colours on the other one... :)
Personally, even your "other work is full color" I think you should follow your first idea: "This will be the One" that I would like to translate by "If I must one day begin by a great B&G work, it will be probably this one.. and your love of this B&G tiger will offer you new future B&G project ideas ;)
In your case, I always ask my tattoer what will be the best choice from his point of view and it was always a good decision at my eyes,too.