I run a cherokee chief mk2 in o.m.r.a. z class using a .12 ic engine on a gearbox. I guess with a full tank of fuel, my Cherokee prob will weigh a lot more than running fast elec.
The main problem that the mk2 has is that the nose likes to come up and run on its transom, thus the fitment of trim tabs is a must.
I am also using a stinger drive which is set approx 1mm high at the thrust washer end to the bottom keel line, using a steel rule placed on the keel edge.
Getting the boat to run perfect took a lot of setting up to keep the nose down, but was worth the effort as she won me a 3rd trophy on its first race meeting at the end of last year. See Feb 08 issue of model boats mag. Every body that has a mk2 in o.m.r.a. has had to play with thiers an set up, but when going they do perform very well and also good in the chop.
also a must is the fitment of a turn fin.
Hope this is of some help, Gary C.