I dont see how an arm coming off the vertical pole will increase the dump angle, once the scissor arms goes straight, that's it. Maybe lift the trailer to the required angle, make a bigger scissor arm to fit that, then let/make it collapse all the way down, then try to lift it up and see what breaks.
See this is what happens when you didn't spend enough time studying geometry in high school.
Taking the bottom of the winch beam and moving the location forward
would tip it's angle to the back some. It still would require some
modification to the scissor. It would allow for a little greater dump angle
without adding height.
These military trailers are not dump trailers. The "hinge" polts at the rear of the tongue are not in line, and something has to twist.
The intent was to unfasten the rear of the tongue, and pivot the hitch upwards on the bolts on the front of the box, for compact storage and transportation.
pivot point when dumping, the angled section of part 11:
1993 NH 2120 (the best), 1974 MF 135 (sold, but solid), 1947 Farmall A (bought, sold, bought back, sold again), 1956 MH50 lbt (sold, in 1980, darn it)
Last fall I bought for cheap a (barely) used DR VersaTrailer which uses a winch to lift. Unfortunately, it also uses an arm on the winch tower so you can lift a heavy object next to the trailer, then swing it over the bed and lower it in. I used that feature exactly once, but it did work well. It makes the whole contraption tall for driving around my plantings. I pull it with a CC garden tractor, which works most of the time. The trailer itself works well and carries weight (cap. 2,000#) well, too.
I like Jeff's MUTS's lift tower, which I think hinges at its bottom fore-and-aft. I'd like to leave my tower and winch, but remove the awkward (and quite high) boom and replace it with a similar pivoting tower post. It's on the to-do list, though not alone.