I went through the whole deal with the same install when I had to get my electrical inspected. In Canada and think the USA is the same, but there won't be a 25 amp breaker, so you have to use the next size up which is 30 amp, but now the old rules of wiring size to breaker don't work like they use to, with all the new temperature de-rations of wire and what not.
But here's what I did to get the ok from the inspector. The motor on the power unit did not have any internal or thermal protection and was over the limit in hp for not requiring it, so it need to have external motor protection, that's where the problem came up. The motor shipped with the lift did not state a clear service factor or overload capacity. I had to wait for months and they finally shipped me a made in USA powerpack that had the service factor to calculate the external overload properly. I have 30 amp breaker, and 10 awg and I bought wire that didn't need to be de-rated, then I used an external manual starter/overload with high temp wire to meet the specs on the motor nameplate and mounted it in a box on the hoist.
The inspector said I could have put it on a plug, but by code it would have to be plugged in and unplugged every time i used the motor, if it caused a fire and was found to be plugged in unattended then it would be considered against code.