Got My 2016 Prez Proofs In My Dansco 7186

I like the idea of using the 1979 "Carter Quarter" to fill the Carter hole.

The 99 SBA for Clinton works. Maybe a 2001 Sacagawea for Bush 43, but not sure what to use for Bush 41. The 1981 SBA is clearly a Reagan era coin, but he has his dollar.

Although I'm not collecting this series in the manner you are (*), my suggestions would be as follows (with reasoning in parentheses):

Carter: 1979 or 1980 SBA (legislation authorizing coin signed by Carter; Carter was in office through all of 1979 and 1980 and US Mint designed coin under his administration)

Bush 41: 1981 SBA (tough call here, as he didn't sign any major coin-based legislation other than that for commemoratives, and none of those would have been small-dollar sized, and no small-dollar sized coin was issued during his presidency; 1981 SBA suggested only because Bush 41 took the office of VP in 1981, and that's the closest I can think of -- Bush 41 did carry out some presidential responsibilities in 1981 in the aftermath of the assassination attempt on Reagan)

Clinton: 2000 Sacagawea ($1 Coin Act of 1997 authorizing coin signed by Clinton; Clinton was in office through all of 2000 and US Mint designed coin under his administration)

Bush 43: 2009 Native American $1 Coin (Native American $1 Coin Act authorizing coin signed by Bush 43; Bush 43 was in office during the first 20 days of 2009 and US Mint designed coin under his administration)

Obama: 2010, 11, 12, 13, 14, 15, or 16 Native American $1 Coin (Obama not mentioned in your original post, but there are two blank holes in that album after Bush 43 if there's any desire to fill one of them on account of the 44th president; these years suggested only because they are years in which Obama was in office; 2009 would work too, except that I already suggested for Bush 43)

(*) - If anyone cares, I'm collecting the Presidential dollars series by means of the first day coin covers, most often patiently waiting on the secondary market to buy rather than pay the high price for these products if buying directly from the mint. It's a slow process, but I'll get there someday. Obviously, given that no coin covers will be made for Carter, Bushes, Clinton, Obama, and their successors, I guess those will forever be holes in my collection. I understand the motivation to not have coins for living people, but it would have been nice if the legislation had provided for the Mint to "catch-up" at a later time for presidents that were passed over due to still being alive when the program ended this year. Like something that would have allowed the Mint to issue a coin for a president x number of years after death. Seems really odd that the series not only ends without inclusion of 41-44 and thereafter, but also skips 39.

Hmm. Now I am thinking it might be fun to get creative with some sort of counter stamp.