Ask IH: I want to invest in SaaS

I want to ask you for an advice. I want to invest in a SaaS business. The business is steady and since one year has a constant growth - 20 customer per mont without doing nothing (LTV 550$), MRR 8k $, churn 10%. The founder has over 8y exp in the area of this business, software is really good developed (JS and no spaghetti code) so it is easy to scale. IMHO we could do it 10x bigger with 200k. The problem is that one VC is already there with 500k invested.

What questions should I ask?
How to evaluate it and calculate. A value?