TD Mechanics - Costs, Damage, Hit Points, etc...?

I know this is all very subjective and is a fundamental part of how tower defense games differentiate themselves from one another, but I was wondering if there are any good resources out there that helps define cost structures for turrets, points for enemy kills, upgrades, etc...?

Right now I'm using rex's CSV2array plug-in and a spreadsheet program to manage most of my bulky data for similar sprites that require lots of default stats like max HP, speed, etc, especially since I'm using free C2 and don't have families. You can find it here:

construct.net/en

So I use CSV2array for stuff that doesn't change in-game and instance variables for everything else with a few global variables sprinkled in for single values like total score or money.