Insights you may gain at YC may help you either pivot or improve the current SaaS you have either from an offering or operational perspective.
Most importantly folow your gut feeling because that's what got you to $8.5k MRR. If there is even a 5% chance to improve your product or increase your revenue or both, you should take it. Define your success metric and proceed accordingly.
Hope this helps you :)
I'd make sure that OP knows what they would do with the funding before answering their question. More money does not directly mean growth. It means resources to solve problems. If growth is stifled due to things that can be solved with money, then VC funding is one way to solve it. Not the only way.
So I would not jump to metrics. Metrics are a way to measure progress towards goals, but you first needs to identify goals, and outline what problems exist in the business that are preventing those goals from being achieved. Then identify possible solutions, and determine whether or not money is the roadblock to implementing those solutions. If the answer is yes, then pursue money. If not, pursue whatever the solution is.
Metrics come into play once you've implemented solutions, to determine if the solutions are working.
I understand that I, of course, should decide it based on our goals. Thank you for your advice!