Find one or two strong leads to commit to your round. Make sure these are experienced angel investors. Make sure they love what you do. Make sure you love working with them. Fill the rest of the round with people committing to smaller amounts. In my experience, it is hard to set a limit here. Do what feels right. If someone offers you money along the way, do take it. You can care about your valuation later and the way bigger risk of your business is running out of money. Spent 80% of your investor time with your leads. Limit the money you take from VC's in your angel rounds. Just my two cents.