I just bought twelve 20w led 48" long single lights off amazon yesterday (prime deal on them $5 per light which is pretty reasonable). I've been using the lights in my garage for the last year and am super impressed with them. Here's the link for the six pack set. https://www.amazon.com/Barrina-Integrated-Fixture-Utility-Electric/dp/B01HBT3BVM/ref=sr_1_5?dchild=1&keywords=barrina&qid=1602802070&s=hi&sr=1-5
I have two food safe racks from costco that I'll hang them on.
I mention them because I watch a yt channel called "on the grow". They're the mad scientists of microgeens. They've done experiments with all types of lights, growing media, varieties of greens, etc. Pretty much everything anyone could want to know. Here's a video of their basics to growing. https://youtu.be/D3vnBEvYDZo
Good for simple home grows, or more advanced. Easy going couple that are very informative.
Anyway, they use the same lights, and have had great results with them.
Yes, I would guess removing two of the four lights from your existing lights would be fine. With microgreens, you want them to "stretch" for the light. More light is going to keep them shorter which is not ideal for harvesting.
Trueleaf is the place to get seeds if you don't already have a source.
I've only grown sunflower, and pea shoots so far, but it was super simple.
I'm going to experiment growing with cheesecloth as the growing media and a little bit of nutrient solution. No soil/perlite/coir etc. Super sanitary if it works.
Good luck, it's not hard to do at all.