I used to take 140mcg. I did that fine. I'm 100% sure I could keep upping the dose without crazy cramps. It's all about tolerance, taurine, potassium, water, and other stimulants such as caffeine etc. You should not just jump into 100mcg like that, unless you ran it last time couple days ago. If you have taken 2-3+ weeks off, you can start from 40mcg (which I prefer to start with instead of 20mcg to get a nice first day on it). Studies show the receptors are reset after that time mark (I'm not 100% on the exact time).
What I'm saying is, I got the same effect, if not more, from 40mcg, as 140mcg. Why? Because I gradually increased with 20mcg every two days. That's how you get the same effect throughout the cycle, and not adapt to the thing. If taken at 100mcg. You will get used to it quickly. You would need to up it within a few days. And then, how much are you willing to take to get a "decently long cycle?". Always start off with 40mcg, or even 20mcg with a clean diet + caffeine (some people cut it away when on clen cause it's too much for them. Why would you cut the caffeine? Cut the clen instead until tolerated.)