Hi Coaster.(my english is very poor.sorry) I go to sea fishing with my tarpon 160.İt is very speedy and stable when sit.I don't afraid any weather.I go to 15 km.one a day with my tarpon.when I fishing a windy and wavy day, little boats go out.I love my kayak because I a feel safe always.I am 5' 9'' and 154 lbs.I did not try for stand on my kayak because I don't need stand on my kayak.I thing you can't stand on tarpon 160 when fishing.
I can stand on my 160, but very wobbly and wouldn't want to cast or fight a fish while doing so. I am 6' 1" and weigh 220lbs though.At your size you could probably stand ok on a day with no wind, but no where near as easy or stable as your ride. Not to say the 160 isn't stable, because it has great secondary stability. It just wasn't made for standing. She was made for gliding,which transfers to an easier leisurely paddle or speed when you need it.
I wouldnt say youll stand with ease on the 160. The 140 will be better but even still these are performance boats. To better know how the boat will react to you I would need to know your height/weight.
One other option to look at is the new 135's. They are faster and more efficient yet still have that amazing stability. they are even better designed for the standing thing than your current ride.
You can shoot me an email at email@example.com if you want to discuss boats a little more.