Thought I'd ad some video links for this combo. It's a PA-11 but close to the J-3. https://www.youtube.com/watch?v=OTrNP755-7Qhttps://www.youtube.com/watch?v=j4SAsksi5Bs
There should be some still photos on this site somewhere of the PA-11 with nose wheel installed.
If you sit in the back and have the tailwheel installed it's possible to land 3 point with mains and tail but as soon as you slow down and use
any brake it will tip back onto the nose wheel. Sitting solo in the front seat solo you can just drag the tailwheel but I usually installed a Tripacer skid
for less weight and better rudder feel.
Takeoff distance shorter on tricycle gear because streamlined at start of roll and can rotate to higher deck angle with rear gear placement and no tailwheel.
Rough field not a problem unless heavy braking needed. Nosewheel can be held off with a little power when solo in rear seat.
Dirt on the non chromed nose strut is a problem. keep it lubed and greased.
This PA-11 is 85hp with electric start one 18 gallon wing tank and metal prop. G25 battery in box behind baggage so CG is similar position to J-3
Placards rear seat only solo for Testerman tricycle kit and front seat only solo for the PA-11 with 85 hp and electric start so they are conflicting.
Solo stock J-3 works ok either seat but prefer the back solo. More leg room and better visibility in the back. Plus no feet rubbing each side of your rear.
Add mods to the airframe then what seat is allowable is a factor of CG limits. Stock cub CG computations not needed according to manual if CG falls in a certain range.
The actual CAA card with weight and balance station locations is helpful if you can find it then reweigh to get actual location. Few are accurate.
"Perfection is finally attained not when there is no longer anything to add but when there is no longer anything to take away." Antoine de Saint Exupery