Ppfd, wattage, par or lux

I’m growing with white leds between 3000-4000k and trying to figure out if it’s worth it to buy a quality par meter. I was planning on buying a lux meter and doing the conversion. I’ve been relying on watts per sq so far. Now that I’m trying to figure out which strains I’m focusing on I’m trying to cut down on variables with ofcourse lighting being one of the most important ones.

I use HPS, but a Lux meter and math hasn't failed me yet.
I'd save your money. Go with the $20 Lux meter.

I agree with @.Smoke but even without any tools, there's enough information out there now to get an idea of what's going on.

I have a tendency to lean into overkill. My next cycle I’m trying to do sog at a lower then my normal wattage. I have an idea of the bare min it should be at. But there’s things like canopy penetration, depth ppfd start falling off, coverage limits, and dialing in when I’m starting to waste energy. Hps usually bleach and led can do the same but I assume that I’ve wasted more energy before it’s to that bleaching level