Don't forget a servo is rated with a 1 inch arm so 50 oz at 1 inch is 75 oz at 3/4'' and 100 oz at 1/2'' more then enough for most 40 60 size planes unless your flying on the fringe ..
Also you can get low end digitals for under 50 bucks I never understand why some people will go through 2-3 planes at 100-200 bucks but not want to spend the money on good servos that will last for a lot longer then most planes will
plus the fact that you will enjoy much better control over your plane