I think Shatter was designed specifically to keep players guessing. There are predictable patterns and by 15:00 you know more or less what the rest of the spawn patterns will be.

This is probably not accurate, but overall it's something like:
All small ices at 19:45 = Big Ices at 14:00, 12:00, 10:00, 08:00

Otherwise always a Big Ice at 19:00

Then Big Ice at 16:00 = Big Ice at 14:00, 12:00, 10:00

Or Big Ice at 15:00 = Two Ices at 10:00

In all circumstances all remaining ices always spawn at 8:00

etc. etc.

I have macros where I'll call out a Big Ice in 30 seconds at 16:30 each game even though one might not spawn until 15:00. It keep players on their toes. I guess I'm not totally opposed to having timers remove any mystery, but it does remove a lot of carry potential from a team leader who has the ability to make good calls.