Problem is when I have the front and rear wheels adjusted at say the position for 2" the front wheels are much lower to the ground than the rear wheels. I think I need to first adjust what I think are called the draft rods attached to the front of the deck to lift the nose of the deck to better level. These are like threaded rods. I believe this as when I lowner the deck the front wheels hit first then settles a bit before rear wheels hit. Lastly trying to figure out the height adjustment knob and wing piece up top for 'height adjustment, I believe this piece acts like a height 'stop' when lowering deck but hard to see how it functions and not sure if I should tighten the wing against knob or against sleeve over threaded rod.
Not quite the same tractor, but I just went through levelling my JD LA135 last weekend, and it sounds like the basics are the same.
Make sure tire pressures are OK.
Park on level surface & set the cutting height to what you usually mow at, measure & set the side to side first. I measured to the very bottom edge of the cutting deck, at each rear corner. Should be about 1/2" less that what height lever says - but that figure is not quite as important as getting each rear corner the same. Adjust the nuts under the rod sleeve to set. (That's likely where there might be some difference in mechanisms over the years).
Once you get it right side to side, check the front middle edge & set it so it's about 1/4" lower than the rear corners, using what sounds like your front draft rods. Mine only has one in the middle - sounds like yours has two?
Then, once you get the deck right, you can adjust the wheels by moving the wheel bolts up or down so the wheels are about 1/2" off the ground at cutting height. (Of course, if they're hitting the ground when you do the levelling above, you'll need to first raise them or take them off so the deck isn't resting on them).
My manual said to measure to the bottom outside tips of the blades for all this, but after checking, it was easier to measure to the bottom of the deck, and each blade had the same height difference to bottom of deck.
This was the first time I had gone through this with mine, I had just been using it the way it came from the dealer 5 or 6 years ago. My wheels were way out of adjustment for the height I mow at (I mow tall, they were set for short), it was tipped to one side, and it was way high on the front. So was cutting grass twice, back & front, with each pass. Seems much better now after one mowing.
Most important thing I found in that exercise, before I did all that, was remove the deck & get rid of the buildup underneath (I was amazed how much dead grass was stuck under there, the blades were pretty well up against it), wire wheel the bejeebers out of the underside (remove blades - I used a grinder with a big wire wheel), and re-paint. Mine was starting to rust, kinda bad for the age I thought. Funny how a little job like levelling a deck can snowball into other stuff...