Just smoke/blitz, and support your tiger. Every scenario you should here should kill your tiger (if you engage/ or stay to fight it), because it is way more resources then just one tiger. The way i see if anything you loses a heavy tank, be it a Kt, tiger, or a is-2 is because you messed up. All heavy have way to much health from them to be just killed, unless you put them in the situation.
Couple things wrong with what you are saying here.
1. You don;t always have 60 munitions floating in the bank nor do you always have smoke either.
2. You said they only die if they are in the right situation for it. You are talking about a tiger that is over extended. Sometimes that isnt the case. Sometimes its the enemy who is frustrated with your defensive playing tiger and want it dead. So they decide to katusha your pak guns and rush their armor at your slow tiger. It not your fault for losing the tiger. Its them playing as allies correctly. For close to the same price, you can get 2 T34/85s (one step down from panthers but with AI power) with mark target.
The point I'm trying to make here is that the IS2 can get away with alot more dangerous moves than the tiger because it bounces more shots and more importantly, it can get away from sticky situations without needing smoke and blitz. Of all the heavy tanks, the tiger is the hardest to keep alive. Even KV1 can get away more easily than a tiger and has only 30 less armor.