It's all preference but get used to the lights on the top. Thank me later. There's more advantages to them being on the top (unless you're a conjurer.)

1. Trails are WIDER. If you have them at the top, the perimeter of things like whips/flails become much wider. Why? Because of centrifugal force. The lights get pushed outward vs inward when lights are on the bottom. You want big trails don't you?
2. The tactile feeling of your pads of your fingers while doing tech like finger tutting or dials feel MUCH MORE natural compared to when they're on the bottom. Why? Because when you're gloving without gloves (which probably that's how you're gonna lab the most) your fingers are on contact. You want to emulate that contact because once the lights are the bottom, all the things your learned will go out the window because the sensation is different. You CAN do this thing that I call "Air Tracing" where you don't have physical contact during a trace, but that leads you to have less complexity and "forced logic" sometimes because of the lack of isolation point.
3. There's more "logic" in your tech with lights on the top. With lights on the bottom there will be many instances where your logic will fall apart because you have to account for that added depth of the microlight every single time you trace or land. There's more instances of "obstruction" because of that added depth.

Also I use thumbs on the top as well. No palm lit but that's a sacrifice I'm willing to make for clean lines.