To be honest, I really don't know the answer, but I can't toss you a few suggestions. First of all, I've not heard of anyone frying their alternator yet. I'm sure it's possible, but I've not seen it yet. My personal recommendation would be to stay below 30 amps if you can. It also depends on if you have any extras on your vehicle like aux lighting, upgraded sound systems, rocket launchers, etc.
How many amps are you wanting to run?
Give a man a match, and he’ll be warm for a minute, but set him on fire, and he’ll be warm for the rest of his life.
2000 Pontiac Grand Prix GTP 3.8L SII S/C'd
15%-20% MPG increase at 1.5 Amps
2000 Jeep Grand Cherokee Limited 4.7L V8
No gains.