Thanks for the comments. PBLAIS, sounds like your setup is the same as mine.
I had communicated with Mystic and believe they have good quality. Also worked with Tops in QUality in Michigan, which also has a good rep.
On my boat, with height of the rail, the 70", whether from Mystic or TIQ would have stuck up quite a bit. Something like 68-70 would be preferable to get aboard, though. My existing transom ladder is 21" in the water and we have swum off it, so I am probably going to do the 64" ladder, with 24 in the water.
Somehow, TIQ seemed more responsive than Mystic to my inquiries and more interested in a custom fit. However, up front, I believe both are excellent high-quality makers, and I''ve heard nothing but good things from both. And the ladders aren''t cheap is right--700-800$ or so.