I've only seen it as an e-book but you get lifetime updates. It was well worth the $50 I spent on it.
I bet it was, considering it's now $99!
So one of the cool things about the SB/BB community is that you don't realize how accessible people are, until you realize how accessible people really are. Go through the ABCA and NFCA podcasts, and nearly every guest is giving out their contact information at the end of each show. One of the coaches summed it up like this - go into a diner and walk up to two football coaches discussing pass coverage, and they're likely to tear up and eat the napkin they were diagramming plays on before saying hi. Walk up to two baseball and softball coaches discussing bunt coverage, and you'll probably be invited to join them and risk having the kitchen close before you get around to ordering food.
Yeah, this was a long-winded way of saying - just email him and ask which he thinks would be better for your situation?
As for a library having the book - I don't know - but worth asking about. (Although the additional cost of special formatting to release another version may be prohibitive.) The other thing to add is that if you buy it, you also automatically get any future updates.
Still worth it. I can think of a bunch of different pieces of gear worth $100 or more that I've had to replace multiple times over the 7 years my DD has played this game - I might be $1000 into cleats...and bats...and gloves...and catcher's gear...and half-drank Gatorades...
Your $100 investment will serve your 2 kids for the length of their playing time. $100 / 2 kids / years in the game = a pretty cheap performance boost, plus a healthier arm.