I’ve had the privilege of owning both a -12 and a -14 I enjoyed them both. The -14 is narrow up front and not really great for 2 large adults. Also, its a bit nose heavy with 2up front. With one in front and one in back it was good. The one I had used the long mount. You don’t get much more weight on floats either- #1850 if I recall correctly. There is no provision for floats on the -14 Type Certificate so you’ll need them field approved. If your going to use it for training, it’s going to take them a flight or two to get used to having the left hand on the stick. Upside of plane is that if you were using it for guiding, with the front seat removed, extended baggage and a pod, it’s got a TON of cargo capicity.
A -12 with the #1935 up gross and flaps is a great plane all around. Lots of room in both the front and back seats and the capability to do 95% of what a super cub cub can do. Hard to beat and they can be found at a reasonable price. Downside- it takes a lot of mods to make it a really tough working airplane. Both the flap mod and the #1935 up gross require a lot of work so if you can find one, plan accordingly on price. Also, each -12 is different and you often can’t just call and order parts- they often need to be hand fabricated. If I were doing training, I’d look at a -12 with flaps and #1935 weight increase.