Just an opinion here
but, I wouldn't want the maintenance of a 72 inch tiller's tines
because you are going to hit rocks, hard chert type clays, etc. and until you have ever been walked right up out of your furrow its a surprise you won't forget.
I'm not a 'real' farmer for a living ( most real farmers don't even have time for forums about Tractors) they are so busy this time of year in the northern hemisphere because of the Vernal Equinox ( working toward light in the Spring ) if anything breaks during back seeding it kills your production. At any rate, before this becomes an Ag post, real farmers don't use tillers on large tracks for cash cops anyway, a 60" tiller is plunty, I prefer a 42" because of rocks. OB1 rule of thumb, never have three point hitch tilling machinery wider than your rear drive tires!