Heres the FAQ about the lag and minimising the effect:

http://www.futaba-rc.com/faq/faq-8u-q594.html

Other FAQs including the dual elevator setups:

http://www.futaba-rc.com/faq/faq-9c.html

Seems like they would come up with a better work around for this than buy a more expensive radio. This was the second time I had applied dual elevator servos but this was on a competition plane so It was bugging me what was wrong. Took me some time to figure it out since the endpoints were right. I also made sure servo arms and linkage were the same length etc...

Anyway, a new radio is in the budget but the equalizer or matchbox will do for now.