7040 pressure plate conundrum

I think I may have been among the first to "double-spring" the Power Director type torque limiter back in late 1976 on a strong 7080 tractor. You must use longer grade 8 bolts (at least 1/4" longer/maybe 1/2" longer) and add a 1/2" lock washer under the stool to make up for the second Belleville pressure spring thickness. It works good and can still slip a little bit under severe shock loads. The early Power Shift transmissions used the coil spring design flywheel and pressure plate design because they were concerned (in prototypes ) that they may need release fingers and a throw out bearing to uncouple the engine for easier severe cold weather starting. As it turned out, that feature was really never needed, so they dropped that design and made both transmissions the same torque limiter style.   If that was my 7040 pressure plate, and knowing what your intentions are, I'd buy 6 Gleaner combine feeder beater slip clutch springs (M2-L2) and stick them inside of six of the existing springs, equally spaced. The Gleaner springs might have to be shortened a bit with a cutting disc, and you'd have to measure that, but it will make things so they don't slip with more HP.