1) Congrats on the Merc, they always bring a smile to my face!
2) Silver FDRs don't have added value beyond their melt value unless they are at least EF-40. Therefore keeping them in a glass jar, plastic bag or tube is just a good as flip and cheaper.
3) There never has been a premium on coins from a "relative" low mintage year only absolute low mintage. 40 million does not qualify as low mintage. There are simply too many of them around.
Example; 1950 nickel, mintage, 7 million, no premium, 1950D nickel 2.5 million yes premium)
4) If you want to set aside current coins that will have greater than face value in future, I would suggest unopened solid rolls (pennies, nickels, dimes etc) and of course error coins