Hesston 4600 Baler Upgrade Advantages

I have a Hesston 4600 small square baler (1980 vintage) that I have been using for the past 10 years for baling grass hay.  It seems to work ok but tends to produce oversize bales when the windrows get big (maybe 2-3 ft high and 3-4 ft wide). I try to make a 70 lb bale, 14 x 18 x 42 in long to fit into my bale wagon. I try to slow down or speed up to keep the intake full of hay to try to keep the bales a uniform wt and length.  .  It will take a lot of hay at the higher speeds, but I run the risk of plugging the intake or getting huge flakes and bales too long for the bale wagon.   I have about 35 acres of irrigated grass hay and make 2 cuttings per year. Production varies from 75-100 ton per year. I'm thinking of upgrading to a Hesston 4550 or 4570 or a 4590 or possibly to a newer Heston 1838 or 1840.

 

The 4600 plunger has 92 strokes per min. The newer models have plungers with 100 strokes per min. I am wondering if the newer models will bale faster than the 4600 and allow better control of the bale length without reducing the speed so drastically.  It probably wouldn't hurt to come into the 21 century with my equipment. 

 

Am I thinking straight? Will I gain anything by upgrading?

 

I bale with a JD 6415 100 hp tractor.

 

Thanks for any input.

Hesston 4600 Baler Upgrade Advantages