Hey Ger (sorry, catching up!!!)
Welcome to the forum !
As Andrew said, any plane can be a tow plane. Just need a hook (as close as possible of the CofG) and a strong release servo (just in case !
)
Also, for the power etc etc, I think today's tendencies is to fit the biggest engine possible to tow on an airframe...
Just to say that a few years ago, we used to tow 4 m gliders with a 15cc without any problems... 5m possible, but you need a good tow and glider pilot (and not be in a rush
)...
144 twin, you should be able to tow pretty much everything in Ireland, except the old exeption of course, but as far as week end models goes, you are more than Ok