72 sovereign....which water heater? Need help soon!

[72sovrn]

I am in urgent need of a new water heater. After reading the related posts, I am still not sure which atwood heater will fit into my AS. The measurements that I'm getting seem to suggest that only the 6 gal will fit, but I see some have put a 10 gal into a sovereign. Which one will fit with minimal to no modifications? I might actually prefer to go with a 6 gallon, but I am now concerned that it will be too small for the opening.
Also, how much electrical rewiring is required to install the electric/lp model and is it worth it?
Any help is greatly appreciated. I have to order this by tomorrow at the latest.
I will most likely order from this site, so if anyone wants to give a model number recomendation, that would be helpful. My AS is a 72 sovereign.

http://www.rvcatalog.com/default.asp...5JC6FMBA1SBQZ9

Thanks very much.

[thenewkid64]

The side bath units had 6 gallon water hearers, the rear baths could come with either. If the 6 gallon is what came out, I would use the same size. The ease of adding the 120 volt option is also based on bath location. The heater should be fed by a separate circuit from the main box. To do it any other way you could easily overload the existing wiring. In a rear bath the box is close, in a side bath the box is awfully far away.