Grow light question

It'll work. it'll create more heat and need more watts per sq ft of coverage, but at 100w the extra heat will be irrelevant in most cases. Much bigger deal with more watts invovled. figure 2.5sq ft of coverage over 12 hours - hang at a distance that properly focuses light on this sized area - preferably with reflective walls, too. A free klux app can help do that. You can go maybe 3.75sq ft over 18hours and hung a bit higher for an autoflower. so, keep the plant to an appropriate size and you'll have decent results. Do a small plant with 4 colas and can probably do 100 grams. Maybe 2-3 weeks of vege is all you should do. Depends a lot on how fast your plants grow. as far as the vege/bloom modes. i'd use these both in flower, of course. You only need 66% of the power over 18hours as you do over 12, so there may be a little trial and error if you don't have a dimmer and only those two 'modes'. Hopefully they designed it intelligently and the vege only mode will be roughly 2/3rds of full power. Could count the diodes related to the flower switch and do some simple math to figure it out. No problem if not.. just have to do a little trial and error with hanging distance. Watch resulitng growth. IF nodes are too tight, raise light. If nodes are too spread out, get it closer. Simple as that. Take some notes when you find that goldilocks zone with perfect growth pattern. Hours of operation can be a 'dial' for daily amount of light provided, too. Just don't give too long of a dark cycle in vege phase, and it's another tool to fine-tune how much light you give.

Probably use bloom mode for 2-3 weeks during the stretch, then just blast with both for remainder. My rule of thumb is 80-150w per plant you want to grow. Should be enough for a 1 decent plant for sure. Blue light suppresses extension growth not good when you need to stretch but beneficial once stretch is over. In general, blue light enhances compactness and makes plants bushier. I done some testing with my shitty bluurple a longtime ago, checked to see what PAR I'd get from both veg and bloom modes. Actually get a little higher PAR out of veg than Bloom, red photons hold about half the energy of a blue, veg had a higher ppfd overall but the margins where nominal, with both combined won't hurt anything.

I have never seen a double switch light. Interesting. No you should have the veg during veg and flower during flower. I can only guess the light increases intercity of turns on some red bulbs for flowering spectrum. 100 watts for one plant should be more than fine using modern led technology. However cheap leds never really perform as specified.

Veg in Vegetation Phase and both in Flower 👍