The second missing card is #563 Pete Cimino and Cesar Tovar of the Minnesota Twins.
The third missing card is #590 Bill Skowron of the Chicago White Sox.
The fourth missing card is #544 Joe Hoerner, Joe Kernek, and Jimmy Williams of the St. Louis Cardinals. The extra space shown is for #570 Art Mahaffey, which is currently on the way through the mail system.
The fifth missing card is #556 Mel Queen of the Cincinnati Reds.
The sixth missing card is #547 Horace Clarke of the New York Yankees.
The seventh missing card is #561 Choo Choo Coleman of the New York Mets.
The eighth missing card is #591, which is a NL Rookie Stars card featuring Bart Shirley of the Los Angeles Dodgers and Grant Jackson of the Philadelphia Phillies.
Although there are only 8 cards left to go, the time it could take for me to complete this set is unknown due to the high costs of high number cards from the 1966 set. I've set my limit for final series purchases at 30% BV (normally 10%-20% BV). Even at this limit, it's difficult to find high-series cards for purchase. For example, #591 books for $40 yet the cheapest Buy It Now offer on Ebay right now is over $98, which is almost 250% BV--insane. I'm looking to pay $12 for this card, so it'll probably take a while.
In the meantime, I'm also working on other vintage sets. For the '60s decade, I've already completed 1969, 1968, 1962, and 1960. My 1965 set is missing 1 card, 1967 is missing 11 cards, 1961 is missing 76 cards, and 1964 is missing 92 cards. The only '60s set not really in the running for completion is 1963, which is missing 280 cards. I'll just continue to follow the deals, which seem to rotate throughout the different sets over time.