Definitely stay with the AFX if you have that much corn. We have run the ST rotor in corn in our 7010 for 3 seasons are we are not running it another. Felt we could do a decent job with it the last two years... but this year was a PIA!!!! Even when it works decent it is MUCH less forgiving on settings and you will constantly fiddle with it to make it work good. It does not handle changes in yield worth a crap. With the rain we had this year we had a lot of variance in yield in every pass. If it dropped below 200bpa it was puking corn out the back... but at 6.5mph in 230+ bpa corn it did a nice job (at least in the one number i remember). But some numbers we just could not for the life of us get it to work worth a darn.