Need advice on Grand Carpet Mills

A buddy of mine has one for his Staffordshire BUll Terrier and doesn't use it as much as he wants to. I was thinking of getting for my dog, the model he has is the small dog mill which is for dogs under 45 pounds. My dog is 44 pounds, is there a way to measure to know where it will work out or not? I would have to drive 3 hours to get it and I don't feel like going through the hassle if the dog will be too big for it.

This is her

She is about 15 months old, I don't think she can get any bigger right?

 

On the trotter website it tells you to take the measurement from shoulder to ground and between the front and rear legs and add it together then multiply by 1.25 whick should give u the axle to axle measurement (running length). Not sure how accurate that is or if the same principle applies to carpet mill setup. I would think the weight would make little to no difference unless u talking 15lbs+

 

Thank you very much I will look at that.