Come with a name for the small checks that you're raising. "Party Round" tends to work.
Communicate that there's interest, you need to move forward, and they need to tell you what they need and when they can make a decision make.
"We're planning to close the Party Round investment window in 2 weeks. If you're interested, can you let us know when you'll be able to make a decision, and what else needs to happen before you make a decision."
They might ask "What's the current status of the round?" You can say:
"We're in late-stage diligence with a variety of people. We're asking everyone to submit interest by [DATE]".
"Our main criteria is not getting people who can't just write checks - but people who can add value."
You can use Alchemist as a bad cop! You can say "Our advisory board has asked us to stop focusing on fundraising and focus on customers [or focus on larger investors], so we're planning to close smaller checks imminently by the end of the month."