RE: Opinions on Spaniels
Alot of it is in the breeding. There are field trial lines where range/hyperness are wanted and there's actual hunting lines. The ones I've seen tend towards the smaller size and are great hunters. You may want to look at the french brittany. They're smaller and the breed isn't popular yet with the field trialers. That being said, I don't know much about them, how they range, etc. because they are pretty rare where I live. I did see one litter and the pups at seven weeks were small with the mother being around 35lbs or so.
BTW, any hunting dog will need to work out thier energy.