Small update, have reached germination of about 50% on seeds planted at seed swap. Certainly achieved faster using an actual starter mix.
The most recent flower starts were in a 50/50 pittmoss and regular soil mix. Will compare those results as well.
Earlier starts have reached almost complete germination, so I feel good about the odds of these more recent ones, especially with better soil conditions.
Weather is looking up in the forecast, hoping for some direct seed planting soon!