Just my opinion but: I've had my 59 since Hi School (1964) and am totally obsessed with it. I feel the whole 'character' of the truck is ruined if you change the tail light section (or grill, hood, fenders etc.) unless you're doing a complete custom. Mine is by no means stock but I tryed to stay with the basic theme.
So cutting in a 'second' set of buckets below the tail lights would kill me. However the location below the tailgate shown on the red truck & mine is less intrusive. But I believe rectangle is a much better shape (I may be bias) No offense to Walston. There are many rectangular ones avail. in junk yards, mine are dome lights from 1941 Dodge power wagon ambulance that fit pretty flush. I also have a 'spare' set of 59 parking lights I considered but I don't think they are as clean looking but would stay w/ the '59 theme. Also I considered cutting in Harbor Freight clear driving lights.
I did use a 'micro switch' on the column linkage arm as others posted, I like to let others know I'm planning on backing up day or nite. I'll try & get a pict. I also have a manual switch on dash w/indicator light.
It's worked flawless (see note) for 40+ yrs. (2 engine swaps and a swap from 3spd. to 1969 3spd. w/OD)

https://www.ford-trucks.com/forums/p...ctureid=119653

Note: If you use both a linkage switch and a manual switch lookout for elect. 'feed back'. I powered my linkage sw. from the ign. term. so the lites would only come on in reverse w/engine on (not when I was 'parked' in rev. in acc. listening to radio & doing what else teen age kids do).
Problem was I wanted my manual sw. to work anytime so I powered it from a 'hot' line. This all worked great untill I left my manual sw. on w/engine running - now when I turned off the ign. the 12v hot fed "back" if in rev. (which is where I put it to park) and the engine would not shut off untill I took it out of reverse. I think I solved this w/ a relay.