agexpert,

I have exactly the same ARF trainer that you are dealing with. I only bought it because I had just crashed my kit built Goldberg Eagle II and wanted to get back flying quickly. (also because it was on the hobby store wall and was CHEAP lol). I have an OS 40LA in mine and I had to use pretty much exaclty a pound of weight, some of that was a weight on the end of the prop shaft and the rest was the stick on weights attached to the cheeks of the fuselage as far forward as I could get it.