The "chunks" in the beet pulp pellets have been smaller than those in shreds, and mine seem to do better with the soaked pellets than the soaked shreds. They don't turn to complete mush like pelleted feeds or hay pellets, but the pieces are much smaller than the shreds.
I have some pics somewhere of the pellets soaked, can't remember why I took the picture, but pretty sure I have one somewhere.
Ok, hopefully they stay in order when I post, not what I thought I took pictures, but now remember I was taking pics to show the difference between the really good shreds I can get and a batch of icky beet pulp I got (I think they were overcooked, too high temp in the pelleting process). Top pic is dry quality shreds, middle pic is wet quality shreds and the bottom are "burnt" ones (I can't remember if it was shreds or pellets, but thinking pellets).
Beet pulp pellets and shreds are not all created equally, some companies have nicer, cleaner product. The shreds in the pic below are not readily available to me, or I'd still be feeding them. The icky ones in the picture are from the local vet, I think the brand might be Nutrena (she carries Nutrena feed, so would logical she'd have Nutrena or Cargill pellets). Now, when I buy, I just get the Standlee pellets, as they are most convenient for me. Hope this helps a little bit, you may just have to try a bag of pellets and see how they look and if the pieces soaked are small enough for your horses.