Look at one of my early pictures. 4, - 1/2" Bolts hold the hitch to the shank. Maybe grade 5 or above. The single pin that holds it in the receiver is only 5/8" and it was to pull a dump trailer with around 6 yards of soil in it.
Be nice to use bolts that match the hole size in your draw bar.
What I mean is if I mounted the 2" solid square tube to the top of the drawbar with (2) 1/2" hardened bolts. 5,000+ lbs is a lot for 2) 1/2" bolts. maybe I could do 3 bolts or use 5/8" grade 8 bolts.
1900 Pounds of tongue weight does not sound right to me. Sure be nice to see a picture of this thing.
Needs to be strong. Pulling a batwing over bad ground creates more stress than pulling a trailer down the road.
Here's the mower
Woods Equipment Company - Woods BW1260 Batwing