I have a DP Ultimate for 9 years with well over 400 flights on it powered by Saito 150 GK is more then enough power.
It still flies and looks like new .

I have replaced the landing wheels twice over the years. The 150 GK has never failed, great engine.

I don't think the Ultimate was made to haul ***** as you say, but is a very good slow flying stunt plane .

My friend has the DP Ultimate as well, powered by O.S. 160 FX and I have had his plane in the air a few times
BIG POWER from the 160 for this plane.

Pic is about 4 years ago.

Good luck !

Steve