1961 and 1962 Topps Stamps

[deweyinthehall]

I am beginning to dabble in early 1960s Topps inserts, and I have a couple questions regarding these stamp issues:

1) Do people usually collect them as complete panels or individual stamps? I know it depends upon taste, but I'm curious to know if there is a general preference (a quick check shows the obvious - panels are rarer).
2) The 2021 Beckett Guide indicates the 1961 set has 207 stamps, but goes on to say it's "actually" comprised of 208 stamps - how many are there actually?
3) Also for 1961, Beckett indicates only the Kaline comes in both green and brown varieties, but the way the set is checklisted it suggests others are available in more than one color. Is Kaline the only one?
4) For the 1962 set - the Beckett guide says there are 201, but that there are 100 players each in red and yellow backgrounds - this would mean 200 stamps. Are there 200 or 201?
5) It says Seivers is the only known variation - any others out there?

Thanks for helping this novice!