wowanalyzer.com Suggestions for a log
You should use Brain Freeze immediately following Frostbolt if you have fewer than 3 Icicles during the Frostbolt cast. If you have 3 or more Icicles during the Frostbolt cast, save the Brain Freeze proc for Glacial Spike.
icy-veins.com Frost Rotation Guide
Cast Flurry Icon Flurry if you have Brain Freeze Icon Brain Freeze and
you have just cast Frostbolt Icon Frostbolt and are currently at 0-3 Icicles OR;
you have just cast Glacial Spike Icon Glacial Spike.
alterd-time.com Frost PvE Guide
If you do have Glacial Spike talented, the usage of Flurry changes. Cast Flurry If you have 5 stacks of Mastery: Icicles after casting Glacial Spike, or if you have less than 3 stacks of Mastery: Icicles cast it after Frostbolt. If you will have >=4 Mastery: Icicles at the end of your Frostbolt cast you hold Brain Freeze for Glacial Spike.
So there seems to be some differing information about how to best use your Flurry procs when spec'd for Glacial Spike, and it may be that the difference is negligible, but what is the proper Icicle count to be using Brain Freeze procs? 0-2 or 0-3?