Juan....
I am the combat event organizer for the Edmonton Radio Control Society we have a short flying season up here in Canada but combat is prospering here
We have six sanctioned events happening this year in our province.
When I first started organizing I tried to get the club to use .25 ci engines and the events had few participants I was discouraged a little.
Then I moved our maximum engine size for combat back to .46 and things turned around most pilots have .46 engines and planes
If you expect other pilots to buy non standard engine sizes and to use the same type of planes it will work against you for combat.
In my opinion their are too many "classes" in combat today here is our rule "open design .46 ci engine max or 450 watts electric"
A .46 will pull a 60' streamer in just about any amount of wind it is a little harder to get streamer cuts but .46 SPAD wide open is FUN
Hopefully you have coroplast in Guatamala here is a video from one of our events
http://www.youtube.com/watch?v=ngfPwJ1ii04
Don't give up!!!! Darrell