Angel Investing Pre-Revenue: How much to ask for vs How much ownership to give up?

Two other co-founders and I recently launched a SaaS start up in the EdTech space. We are no longer technically pre-revenue, as we are on track to hit about $250K - $500K in ARR (a couple of late stage deals in the pipeline would put us on the higher end of that range), but we all are still working full time jobs elsewhere. We are now actively pursuing Angel Investment so that we can start doing this full time, hire a team, scale, etc, but are in a bit of an odd scenario where we don't know exactly what's appropriate to ask for in terms of investment capital vs ownership stake for a company at our stage. If anyone has been in a similar boat, we could really use some advice!A few questions/comments. If there are resources in this Sub or elsewhere online, please point me in the right direction!We would like to ask for $600K, which combined with our current revenue & cash flows, would allow us to take a salary and hire a few key team members. We think this would give us about 18 month runway.Our industry typically uses a valuation multiple of 5x EBITDA or Revenue (I've seen both) for companies a bit farther along (i.e. Series A and later).We are no longer technically pre-revenue, but we are early enough along where we don't feel like basing our valuation on revenue or EBITDA at this point fairly values the business or the opportunity. $600K funding based on a revenue or EBITDA alone might mean giving up too much of the business. What is an appropriate valuation method for us? The Scorecard Valuation Method seems interesting, but I'm not sure how to assign a reasonable dollar valuation to that when we approach an investor.How much ownership should we give up? We don't want to give up more than 15% at this point, but maybe that's naïve.Any resources on how to start creating shares in the company and assigning a per share value?Should we take on debt at this point instead, and get equity investment later? What about convertible debt? We currently have zero debt and company is fully owned by the three of us. see hubwealthy.com/wealthy