Maximum Adoptable Width?

[Nako]

Or more specifically, what is the maximum width an adoptable can be without page stretching? I'm done with my first batch of revamped Farallon and the shrinking just kills some of the details... so I'm looking to shrink them as little as possible XD  Well, it's actually the cert that suffers the most from the shrinkage. Overall, a lot of factors at play and I have to know just how big the image can be itself. THen I can start toying with Cert size, etc.