With your yields and straw, stay away from 30 foot. The only areas I have seen 94x0s set up with 30 foots are in the Horse Heaven Hills of Washington state and dryland wheat areas of Idaho. Lower yielding dryland summerfallow areas with light straw and 30-40 bushel yields, 50 at most once in a whie.
It appears you are comparing a 9400 to a 9600, not a 9400 to a 9500 like in the original question. The OM for my 9400 states that a 9400 chaffer is 32.75" long. The OM also states that a chaffer for a 9500 is 48" long. The OM continues to indicate that the chaffer on a 9600 is back down to 32.75" long. So, you seem to be correct that the chaffer is the same length when you compare the 94 to the 96, but not when comparing to a 95.
A few years back when I was deciding to buy a 9400 vs 9500, my tape measure also indicated the chaffer on a 9500 is indeed longer than that of a 9400.
Sparrell, my post was meant to say the brochures say the length and width is the same for the 9400 and 9500, not 9600 which I typed. The brochures must be wrong then, because the length is the same in the brochures for all three, the only difference is the width for the 9600.
With our 9500, we would CRAWL in 18' of swath but we usually pull pretty heavy crops. I think you would have to have very light crops to use a 30' but I may be wrong. I would guess 25' max. We found you can chug along in wheat decent but in barley and canola, if you want to keep it in the combine, you won't be breaking any speed records.
If the part #s on the JD parts website are the same, my OM probably has a misprint in it. It definately says (under the spec's section in the back of the book) that the 9400 chaffer is 32.75" long and the 9500 chaffer is 48" long. Wouldn't be the first time I was wrong because of a misprint.
Anyone have a 9500 in the shed that they can go measure the chaffer on? I measured my 9400 this morning and the chaffer is 32.75" long, just like the OM says. My 9400 also has a 15 or so inch extention behind the chaffer, maybe that is where they are getting the 48" stated in the OM for the 9500? They added them together for the 9500 specs, but list them separately for the 9400? Why would they do that?