We had a nh D710 to take over from conventional bales in the early 90s which is the an identical baler as hesston 4600. It did an ok job for us dad bought it new as he didn’t like the idea of a round baler and quite frankly round balers of that era were the crap anyway. We used to stack with a moulton flat 8 grab in the field and chase them back to the yard with little 56 bale buggies into yards etc and stack into the shed on wet days when we’d finished harvest but the baler was very slow in comparison to modern balers but horse people loved them we been did some baling for people that wrapped them in 2s. I think there is one for sale I’ve seen recentlyHave seen a 4600 advertised, quite pricey for what it is but a very tidy machine. I think the 80x47 is probably a little small though really, great for a replacement for small bales but to run alongside it is quite an overlap. I think the D1000 size bales might still be big enough for larger stock units to still take them, whereas 80x47 is going to start verging on "too small and messing around". There is also the factor of smaller hole to push the hay out of -> slower baling.
Very interesting what you say about wrapping 2 bales together though. Do you have any photos of how you are doing that? Do you tie them together first?