I'm sorry to say I've never actually used Rawr and thus can't answer your question about it.
However, I can give you a general way to gear up - the more stamina and armor the item has, generally, the better the item for you. You don't really need spreadsheets for that. That's a very general rule, but that's how EH works.
As for warriors, I don't know on what level you're gearing so here's the steps as I see them:
1st you'd like to start with 5 man normal / HC gear / Cheap crafted saronite gear. [For example, Black Heart is one of the best trinkets you can put your hands on till a certain stage in game, and it drops off 5 man normal ToC.]
Once you get your hands on that, you can start grinding random heroics for Thriumphs. Those should get you T9 quite fast, along with some off pieces to gear yourself decently. Gear of equal level can be bought as BoE items off the AH [Ilevel 232] and drop in ToC 10/OS 25/Onixia 10.
Having full t9 with off set pieces should make you ready tanking ICC 10, maybe even a bit before that.
The next step is Ilevel 245 - ToC 25/Onixia 25 mostly, but many people choose to skip this part partly becouse it's hard to get ToC 25 going nowdays, and partly coz they prefer to jump to better eqp that drops in ICC.
ICC also scales quite simply - ICC 10 gear is the lowest on your want list, ICC 10 HC and ICC 25 are quite equal, and ICC 25 HC are the best. There are 2 crafted items that count as ICC 25 drops - The pillars of might [Legs, BiS for a very long while] and Boots of kingly upheaval [Which are nice to have if you can afford, but can be replaced by the boots in RS 10 and ICC 25 quite equally and prolly be left for people having too much gold.]
The gear there is really simple to decide if it's an upgrade or not - basicly, you almost never have an instance drop gear with same Ilevel and diffrent stats. The few cases that this happens tho, you should be thinking of how your personal char needs to gear up - for example, I've got both the neck from ICC 10 1st boss and the neck from ToC 10 HC. They're similar in the amount of stamina they give - but one has hit, while the other has dodge. Depending on the rest of my gear and the state of my current hit % I'll decide which one to use.
Lastly, as I see it, the only place where you might have trouble deciding if a certain part of gear is an upgrade or not, is when you hit the set bonuses or procs of certain weapons. [T10.5 bonus Vs. slightly better gear off ICC 25 and last word vs. facelifter and other ICC weapons]. I think this is more of a personal choice - I prefer having the T10.5 4/5 set bonus as it gives me another minor CD, while I know another tank who claims he prefers to have the 1-1,5k extra hp he gets with ICC 25 gear. About last word weapon, it was decided on the forums it's not worth having over normal tanking weapons, but I guess that's a personal choice aswell.
P.S. You might want to take a look here, even tho I tend to disagree with them quite often about which item is better over which - www.maxdps.com .