I'm no expert, but I'll throw my thoughts out anyhow.
My thinking is that neps do not need crazy bright lighting. It seems that diffused window light works well for them and overly bright light can hurt them...? Do you have a window situated that you could use for the nepenthes? On the other hand, the drosera will do well beneath bright light. The light strength will be stronger in the center and will fall off toward the edges...I would put the drosera in the center and the neps around the perimeter.
Determining light requirements from specs seem to be problematic for me in that there's lots of info out there on plant needs and on how to calculate the light. I use this website a bit for figuring my lighting. I *think* it's a fairly accurate website in regards to the lighting articles. This is the page I use the most, "Part 2
", but the previous part, "Part-1
" preps you a bit for it.
I had a bunch more written but while I stepped away from the computer my beautiful bride slipped into the chair and surfed elsewhere. Of course her priorities were much higher than mine...she was searching for Christmas songs to carry to the women's jail ministry that she heads up at our county jail so I'll let her slide.
Anyhow, the above is all that was in the cache when I got back.
I'll add here that halving the distance to the plants from the light will/should/might(?) quadruple your DLI but reduce the coverage area significantly. Doubling the distance will reduce the DLI to a fourth of what it was while increasing the coverage area. The 15w bulb will have a low DLI, I would say go on up to the 24w or even the 32w bulb if you can swing it...future-proof for other projects...you can raise or lower the higher wattage/DLI bulbs to fit your needs. The 15 watt bulb will be the most restrictive in adjustments.
Anyhow, I'm no expert...that's worth repeating!
Best wishes and Merry Christmas!!!