The terms of any investment are unique to each company. So it's hard to answer your question in generalities. That said, for Silicon Valley companies, convertible notes usually have a cap set at $4-5m with a discount that is either set (15%) or that is determined by a factor of time. I've seen North American companies at a similar early stage that are outside of the valley raise at as low as 3m cap.

Generally speaking, every round of funding is usually a 10-20% dilution, sometimes as much as 25%.

You want to use standard docs, and not complicate anything. Happy to talk through your specific situation and tell you what I think would be fair for both parties.