Are Resonators available as thru hole parts?
I guess so.
http://www.dipmicro.com/store/XC7-16000
http://www.dipmicro.com/store/C1K22-50
Or even less:
12 cents for both.
Little more space worth the tradeoff to me for accurate timing.
With a crystal, can write a time sketch that's good for a second a day drift.