So if you mixed it with water it would jist be salt water?
I was planning on only taking amitriptyline by itself
Poison salt water, I guess. But it doesn't cause any burning damage.
I'm not an expert, just read the guides about Amitriptyline. I suggest you do the same. My understanding is you really need the other things with it to make it a peaceful method.
Any overdose is going to put you at high risk for vomiting. Antiemetics are in your best interest. You are more likely to fail if you puke.
Long acting benzos are what put you to sleep, so you aren't alert when you have a heart attack due to the overdose. Ami also takes a really long time to work, so if you're awake during the overdose, it's not going to be peaceful at all. The side effects are bad.
Simple pill overdoses have a high failure rate. Cutting corners is what messes people up. Do what you want, but you should be fully aware of what you're getting yourself into.