I would put them at the back in the center and rear stalls over the axles. The weight of the trailer alone, with the axles so far back, should give you the tongue weight you need, 10%-15% of trailer weight. Our Warmbloods weigh 1400#-1500# so which stall they are in makes a difference. Also consider the weight of the tack in the tackroom. If your trailer has the collapsible tackroom in the rear putting the saddles back there can put some weight at the back.
The trailer looks pretty level. Because the Sundowner bumper pull hitch is not that far off the ground, you may consider a drop for the receiver hitch to help level out the tow vehicle. I like a slight nose up for the trailer which would also help.
What do you use your “warmbloods“ for? How many do you haul, at a time?
Good post.