Since no one has actually answered your question, let me try and give you some specific guidance:

The "fair" range would probably land between $5m-$15m pre-money.

For the low-end ($5-6m) to be fair, you'd be in a tiny (measured by total addressable market) with slow growth on that $2m as measured by either Year-Over-Year or month-over-month, depending on the sales model.

Add a million to two million to the total pre-money the higher the TAM with no obvious incumbent to beat.

Add an additional million to four million for better growth and proven, scaleable low customer acquisition costs.

So that's how you would scale up or down a generally reasonable valuation.

I would answer your question with more specificity had you provided the important contextual details like industry, where the company is located, business model, but at the very high level abstract, this should be helpful to you.

Happy to do a call and give you a much more narrow range based on understanding the details..

If you think the value over time is very high, don't spend time optimizing the valuation now. Use the credibility of these advisor/angels to build the story of why you are going to be able to take advatanage of this large opportunity and spend more time optimizing the round following them. They also know there is likely to be additional dilution in the future, so you want them to have a meaningful enough chuck of the business to stay motivated and helpful. This is all an arguement for keeping the valuation low now and increasing it post angel investment.

Safe notes from Y-Combinator are relatively new documents that aim to solve these problems. However if you already have establish an annualized revenue, I'd be tempted to do a straight equity deal. Maybe a anti-dilution kicker.

Fair valuation to invest may not necessarily be the one showing numbers on higher side, even if that exceeds your expectation. Invest your time to to understand the fine prints involved with either investors to be able to conclude the best deal.

Do feel free to DM me or hop on a call to get reviewed anything that you may deem important.