Hi Alex, be aware it’s not exactly easy to reflow a 3030 emitter onto a 3535 board. Far from impossible but they don’t self center and snap in place like they will on a proper 3030 board (LED4Power) or like an XP will on a 3535 board.
Definitely doable but even I’d be warry of trying that triple only having 3 LED’s on hand… Aain you have to manually center each emitter on its pads and hold it in place while the solder solidifies so that’s gonna be a task with 3 at once!