Just putting in my 3 cents, though others have more experience.
I'm a fellow and also moonlight, started a couple of years ago, initially at a small community hospital either doing overnights with consults/ED/ward coverage, or weekend ward or consults/ED days. More recently I started at a state-hospital level for a different moonlighting gig with no ED, no consults, no AMA discharges, and no unplanned admissions. I'd say that I would always dread my ED consults, even a couple of years into it, doing it several times per month. I never got to feeling comfortable with higher-risk discharges, even though I think my clinical thinking has been sound. [As a pro-tip, I was also a strong resident, and when feeling a little uneasy about a decision, I would think 'how would I justify this to an attending, and am I certain that this is the best way to proceed?', then I'd document the heck out of it and I always felt better getting all my thoughts out.] I don't think I delivered bad care, and I can always talk to Master's level clinicians, nurses, or ED docs about my thinking to ensure that I wasn't too far out there - and it was always reassuring.
But long-story-long, I still don't like covering the ED, I still dread those shifts. I'd gladly take 'more acute' state-hospital level patients, where there's no AMA discharges, no turf-wars with other specialties, and no trying to suss out cluster-B risk overnight with no collateral and no great temporizing disposition.
I think the moonlighting helped me to determine that I'm certainly capable of that kind of work, but it's not a great fit for me in the long run. When I no longer am needing to moonlight, you can bet I won't be stepping foot in an emergency department.
Best wishes on your fledgling independent practice.