What ball mount & drop are you using?

I'm looking to buy a ball mount for my receiver and finding it's a rather odd drop dimension requirement. I did the measurements today and tried a couple my friend had that were pretty close.

To achieve the some what standard 18" from ground to top of ball height it looks like a 1.5" drop is near ideal, actually closer to 1" drop might be perfect. But..... that's a pretty hard drop size to find, most are 2" or greater.

My friend did have a 1.5" drop and it measured out to 17.5" from ground to top of ball with a 7" pin to ball center length.

It seems the other option is to use a 2" drop with a 1" taller ball.

My van is setup for 7,500 lbs tow capacity so I'd like something on the beefier side. I'm also looking for something more corrosion resistant as I launch watercraft in salt water some of the time and my last ball mounts from my SUV (5" drop) are looking pretty corroded after being dunked in salt water more than a few times.

Suggestions welcome.

I'm also considering the billet aluminum (think Alumistinger) style but Stainless Steel would be my first choice.