3" might be on the edge of too close for the babies. At that height, you should watch for heat stress. I use about 350 actual watts above and another 350 on each side, for over an actual 1000 watts. Don't let anyone tell you CFl's don't work. My yields and bud quality is excellent, and I'm just an old fart who pays attention to what the babies tell me everyday. Anyone smarter than a brick can do this with patience, perseverance, and listening to the people that have done this many times before. When the second set of true leaves are doing well, drop the lights to about an inch and a half to 2 inches, and again check them daily or they grow so fast you will burn them if they touch the plant. Pisses you off to burn a newly started cola. Peace & be kind.
It isn't that CFL's 'don't work', it is that they just are not as efficient as an HID lamp (or LED). You can use a bunch of CFL bulbs which eat a total 1,000 watts, but you're not actually going to get the light output of a 1,000 watt HID lamp. It comes down to luminous efficacy, and an HPS lamp will provide 2-3x the lumen per watt over a CFL (90-150 lumens per watt). Halides produce somewhat less per watt than HPS, but more of it is photosynthetically active.
Okay so they produce quite a bit more heat; whether or not you really have to run AC and the cost per kWh is going to determine otherwise, but HID lamps could actually save you money on electric compared to a number of CFL bulbs as you need much less energy to produce the same relative amount/quality of light.
In relation to the OPs question, I don't use saran wrap or any kind of humidity dome when starting seeds. I use a potting mix with coco coir and castings which holds moisture very well. RH can get low here in Winter, maybe not too low but dry. If the air is dry the media does dry out faster, but I opt to water it more frequently if necessary. If I did have to use a dome I would ensure it is partially vented.
It is said that if you plant the seed with the tap root end facing up, (or just throw it in sideways, as I prefer it's going to settle anyways) the tap-root is supposed to emerge and orient itself such as to flip itself over and shed the casing naturally.