Is there a way to model my heal values/cast times/HR ticks etc?
Hey, I'm trying to model my character so I can decide which changes I should make.
Is there something in the form of a spreadsheet or maybe some formulas I can use to do this?
Not really. Simulations for a healer aren't going to be anything close to a DPS sim, it's hugely dynamic. The only thing that can be set in stone is that haste provides the most HPS, crit and mastery provide more HPM (although mastery will be better since there's no overhealing risk). Spirit will change from healer to healer and depend on your other healers as well as raid size and comp.
[e] If you're talking about basic cast time / HR tick calculations, the math should be in the Hpally guide and/or EJ for the most part, except for HR ticks since I don't think it's updated yet.