Provided you operate a soldering iron the same capable way as you seem to handle many other tools, I will recommend the small planet-gear driven Kavan starter. Only thing is that you have to replace the wiring with some heavy duty copper all the way to the coals ( Is that the phrase ? ) inside the starter. Operation takes an hour and then the starter will produce so much torque as the Sullivan Torquemaster which is far more expensive and a lot heavier.

If you can not turn the motor with a hanging cylinder remember to consider if you have flooded the engine. These highpower starters can destroy wristpins and pistons and conrods if cylinder head is filled with fuel. Allways handcrank a couple of times ....

Please keep up the info on your 160 as I'm also going to operate one for the next season
Regards Eggert