I used to have transom mounted launching wheels on a 4.2m SIB with a 25hp Merc on the transom. The SIB was a Quicksilver HD, reasonably heavy old thing. At a guess the motor was about 50kg. To be honest it was not something that you would want to take for a longish stroll, if you get my drift
The issue was that the load was unbalanced, very nose heavy. With a shorter SIB you may be better off.
I also found that with the wheels hinged up, they generally got in the way, and looked naff when underway.
You may be OK over 50 metres with a good set of transom wheels, but if it was me, like Treerat, I would try to find a launching trolley or similar that puts the wheels closer to the CoG, and leaves those round rubbery things on dry land.