120mg of methamphetamine is a HUGE dose, I understand recreational users push dosages a lot but the cardiac effects would be pretty pronounced at that level I think
I'm aware of what wiki says about it. I can Google that as well so thanks for the unnecessary copy and paste.
Under Dosage on Erowid it says" Different peoples' metabolisms work at different rates, and drug strengths vary, so there is no way of stating a "safe" or "unsafe" level of use." Furthermore, those dosages are listed under the assumption that you are dosing with Pharmaceutical methamphetamine. Therefore the dosage guidelines are based on its purity and other known factors.
Also, you're listing details for a non-tolerant user starting out. Original Poster has already listed he not only uses but has previously IV'd. Therefore his tolerance levels will be significantly different than what a new users baseline would be.
I almost guarantee that the previous experiences the user had with IV were at doses over 50-100mg and more likely in range of 150-200mg. In the world of IV Methamphetamine doses typically begin at 100-150mg on the low end for recreational use.
Wiki provides factual information for legal and healthy (or indicated) use of substances. It is not a practical guideline in the recreational drug usage world. I'm trying to provide the Original Poster with practical knowledge from 10+ years of personal experience in order to prevent the user from being confused by misrepresented data and worst case scenarios.
Also, the maximum suggested dosage of Vyvanse is 70mg, of course twice the suggested dose has the ability to cause hypertensive crisis and blurry vision due to high blood pressure. Such symptoms are indicated as a possibility for any dosage of a stimulant. Once again, I speak from years personal experience, both prescribed and recreational.
Regurgitating search engine information that the user can find themselves is not useful for anyone.