Changing seat position on the water is very possible for the record contrary to what was mentioned above. Also no amount of comments here will tell you what you need since everyone's got the best, otherwise they'd own something else. Demo Demo Demo! You need to spend some quality time in a boat before you can decide what is best for you and you may make the wrong decision the first time. Fortunately with these name brand yaks you can usually get a lot of your money back out of them and go another route. I won't tell you the Ride 115 is the best cause it's not for everyone in every situation. I do enjoy mine though and I find it comfortable, stable, and a little slow. That being said I'm almost never more than 2 miles from the ramp so speed is irrelevant to me, I can't catch fish at full tilt.
Is the ride stable? You tell me.