[wingnut60]

You need to find a Montana owner with one like the one you are looking at on the Montana Owners forum--should be a lot of action there, worlds' largest selling brand--and find out what the ACTUAL weight is as it is sold. It will be over the 'dry weight' listed, as Stripit mentioned, sometimes a LOT. My '15 Suites I just traded for has a 'dry weight' of 16300--I weighed it on way home with maybe 300lbs of personal stuff in it----18020!!!
You are going to be overloaded--manipulating the numbers won't change that. Even if the numbers happen to fit, you will be so near capacity on everything that just thinking about it will be uncomfortable. I said it before, your rear axle weight will have to be under 7500lbs--if you run close to that weight, you will be stressing the tires to the max.
Best you find a current owner of a similar fiver and see what they have to say....