Wow... things are happening fast here. Need coffee, but I'll try to give some fast answers to a few questions you gave.
So the TRP drivers are dimmable, but not exactly the same as meanwells. They use logaritmic dimming, and meanwells use something else
There are a few ways you can setup the color channels on the Vesta.
1. If you only wanted one temperature, you could just connect that.
2. If you wanted 3800k you could just feed both channels from the same driver.
3. If you would not want to waste driver capacity for tunability (see nro.4) you would have to switch wires around to change temperature. That would give you a wide range of options, but it would be pretty impractical. I'm waiting on a report from a guy who designs electronics on switches or other options that could be used for this.
4. For tunability, 2 drivers are needed, one per color temperature. To have full tunability, you would have separate drivers for both colors, with dimming. This allows you to have total control over both light intensity and color.
So at least until someone can realize some kind of switch solution, multiple drivers with dimming are needed to avoid changing wires.
A little more about Vesta vs EB gen2... Since Vestas are 90cri, its normal for them to have a lower lm/w. The actual drop in efficiency is less then would seem from comparing lm/w alone. I think people here calculated about 10% less PAR, comparing to F-series and EB. In light research they also separate photo reactive spectrum, and action spectrum, further complicating things. For some plants and light intensities it seems they grow better with the less efficient 90cri lights. It's not clearcut though.
It seems that for flowering 90cri seemed to speed up the flowering cycle, so it took a week or so less. Some reported it didn't produce more, others say it did. I don't see any clear picture on that yet.
The Thomas Research Products drivers are also about 88% efficient, vs 93% on meanwells, which are similarly priced. It's not a huge difference, but its still almost double the heat. I made the choice because I see this first lamp as a research lamp. It allows me to play around with internode length in veg, even tuning a different color for each plant separately. Also it allows me to increase or decrease stretch. My first fixture is 2x4ft, so I will later make another 2x4, which maybe does not need to be tunable.
So for example half the space with Vesta strips, and the other half EB's just for flowering. the side with vestas would have double the drivers for tunability. the extra capacity, say an extra HLG would only cost about 45$