Kicker motor question

I’m looking to add a kicker motor onto my 2020 Alumacraft Trophy 185. Does anyone know what size shaft I could get away with? The main is 25″, however, I measured where the kicker will sit and it is right at 20″ from the transom to the bottom of the boat. I’ve heard people say in the past you can use either a 20″ or 25″, but am looking for real world experience from those who have either. As luck would have it I found a 20″ in stock….25″ is back ordered. The Trophy has a similar hull design to the Tyee if anyone is running a 20″ or 25″ on their Lund that can chime in.

TIA

BD – The 20″ shaft Yamaha works just fine on my Alumacraft. My measurements are the same as yours.

If you fish in big waves (Great Lakes LOTW, etc) you’ll appreciate the 25″.

Appreciate the feedback guys. I do occasionally fish big waves on very large water, but more often than not I would be in 1-2′ chop. Since I will be buying new I want to make sure I only buy once, but as stated the only thing I can find in stock is the 20″. Not something I need right this minute, but would like to pull the trigger before the wife tells me no