I am getting things started with Freeze Blade, one of the test subjects in the recordings debate...However, his test method was the chosen method so it worked out well for him to be posted first.
You can consult the Cheat Sheet below for a quick look at damage numbers...If you are unsure of my explanation (when required), just watch the corresponding video. Hopefully this method works well for you and comes in handy in upgrading and researching your Skylanders!
Freeze Blade Base Upgrades
Nitro Freeze Blade Base Upgrades
(I will only Double Up like this for "Special" Characters)
Freeze Blade Damage Numbers
Fore More Detail Consult Videos
Blizzard Blade Path via Nitro Freeze Blade
Ice Sculptor Path via Freeze Blade
Trail Freezer Path via Freeze Blade
Ice Skater Path via Nitro Freeze Blade