Hi Eric!
You’re right, we like using Epson 3LCD projectors - they have good colors and they don’t flicker when you record the projection with a camera (which often happens with consumer-grad DLP projectors).
For outdoor use I would recommend a model with at least 5000 lumens, and ideally fullHD resolution. For the OMAi Mapping Stories Sessions in Raleigh we used a bunch of these: https://epson.com/For-Work/Projectors/Meeting-Room/PowerLite-2265U-Wireless-Full-HD-WUXGA-3LCD-Projector/p/V11H814020
If you don’t mind a slightly less sharp image, you could get a lower-resolution model for less.
Let us know if you need any more help!