Re: to troll or not to troll..
I hate to break it to you , but , you allready have the trolling motor (6HP 'Rude ) .

What you need is a main motor , as I am sure that 16' jon is rated for a wee more than 6 ponies .
You should be looking for a 30-40 HP motor , check the manufacturers plate to find the max. rating .
Johny/Rudes are a good bet , as you allready have the tank and fittings , no point having to carry a seperate tank/hose for 2 different brands .
Also , consider an electric , 45-55 Lbs thrust bow mount , foot control is a plus if it fits your style of fishing .
What kind of waters are you fishing , and , what fish are you after ?