Just like you did a 64 P and D Kennedy and few proofs, however on the positive size just think about how much money you would of spent in therapy if you worked in a Dunk' in Donuts.... all those spare holes.... so many holes ...... and only so much coffee one can hold.....sort of like beer ya never own it only ren't it.
Well, I wouldn't put a Kennedy or a Walker in a Franklin Album. I might put a couple of proofs there. In the Whitman albums, I pretty much always put a coin with the reverse facing out so that I can see what the other side looks like. I usually fill the extra holes with a couple of interesting varieties, as well. So, for the Franklin, you could consider finding a "Bugs Bunny", for example.
I don't bother doing it these days but with key and semi-key dates I know I'd never fill, I'd buy replicas, age them accordingly, and put them in my blue Whitman albums. Examples include Indian Heads dating to the late 1860's, early 1870's, the obvious 1877 and 1909S. I did the same thing for my V nickel and Buffalo albums, as well as for a few of the keys and semi-keys of the early Lincoln cents. This was going back 10 years ago. I suppose one of these days I'll get around to removing them to legitimize my collection. Still, I must say it was nice to fill a hole for 0.5% of what it'd cost to do with the real thing.
Years ago when I goose hunted we had a dog named "Amber" Amber was a great dog....she snatch up a duck or goose toot sweet....except she wouldn't give you the bird unless you gave her Dunk'in much'in well a 1/4 PBJ sandwich also worked...however unless you gave her her pay she could out run ya all day.
I stick with the same type of coin. If the series is still in production then I just follow suit. Otherwise I would fill the holes, which annoy me beyond belief, with varieties, minor errors like a die crack, etc. or proof issues. I do keep the same grade as the collection in the album. No need to mess with it.
I leave 'em empty. There's no label on them so maybe that's the difference. No label means the hole really isn't there. Hmmm.
To be honest if it wasn't for the untimely death of Kennedy the series most probably continued until Congress made the switch to the next half series. That said the Franklin was quickly replaced by the Kennedy....and the last of America's 90 % silver coinage.... so placing the 64 and 64 D as well 65-67 halfs just makes sense to fill the album. As they were 40 % and give a record of a time in history where a lot changed in America.