I'm glad you bought these up. People forget that Topps issued some great metal inserts over the years. I picked up some Argentinean metal issues and was surprised at how people thought they were so strange when Topps had a history of metal 'coin' issues that predated the Argentinean items by a decade.
The 1964s are before my era so I am not interested in a set. I picked up the players in 1964 I collect [Koufax and Aaron] plus a handful of others that were in miscellaneous lots over the years.
The 1971s are a first major pack ripping memory for me too, so I have a sentimental friendliness towards the issue. I have a near set but am in no great hurry to fill it, being as I have my idol Hammering Hank already. I've been getting them at the national every year out of 'junk' boxes very cheaply, so I am content to work the set gradually in the hope that I will end up 'into' it for very little money. Got a nice Cardenas somehow...didn't know it was a toughie.
The other set I'd mention in conjunction with the Topps coins is the 1965 Old London issue. They were made by Space Magic Ltd., the company that did the 1964 and 1971 Topps coins, so they are the same basic design and manufacturing quality, but quite a bit tougher than the Topps counterparts. There are only 40 coins [2 per team except 3 for the Cards and 1 Met] and there are many superstars, but no Koufax. They used Tommy Davis and Ron Fairly as the Dodgers players...weird considering Koufax, Wills and Drysdale were the big stars. Contract issues perhaps? At least there are Aaron, Mantle and Mays coins. They all have blue rims and backgrounds [my favorite color] so I like them as much or more than the comparable Topps coins.
FWIW, the 15 pocket pages from Ultra Pro fit the coins perfectly without any coin holders. For my superstar collection I like the self-adhesive coin holders so there are no unsightly staples visible.