If the posts are strangely positioned then just get a Gotoh.
It's IMO every bit as good as an OFR (arguably better actually) but most importantly, only the right knife is C shaped. The left one is straight (just like Wilkinson trems are) so that it can fit at virtually ANY post spacing

I put it in my guitar (which also happens to have a 16" radius fretboard) and it works amazingly well.
Actually it was just yesterday I saw a Dimebag Explosion Razorback that had a licensed FR and it had exactly those Gotoh-style knife edges.
In fact, it looked as if the Gotoh would be a direct replacement...
As a side note, my guitar's stock trem was modeled after the Schaller one so the string lock screws (and thus the route on the body) were much shorter.
In my case I had to swap out the Gotoh string lock screws for some OFR ones (they were 1 or 2 mm shorter than the Gotohs) so as to make 'em fit the cavity without any routing.
If yours is anything like that Razorback then you won't have to worry about it but it's sth to keep in mind
As for dropped tuning, check out the
Tremol-No