two questions regarding lights and germination!

so for lights.. i'm gonna use CFLs until my seedlings are at about 6 inches.
Then i plan to switch to metal halide. which wattage should i use? my growing space is decently small (probably about 4.5' x 1.5' x 1.5'). how many total watts should i have in there? which bulbs should i use?

also for germination. i know the conventional way to do it.. but does anyone know how to germinate and transplant using the hempy system?

100 watts per 3/4 sq ft rule.. so I'd say about 400 to 600 watt.. course if your buying one look at the 1000 watt switchables too.. they switch down to 75% and 50% as well as handle both Mh and Hps bulbs. As for the hempy portion of the question I'd reccommend this thread entiltled An Idiots guide to Hempy or something to that effect..
https://www.rollitup.org/hydroponics-aeroponics/386008-idiots-guide-hempy.html GOOD LUCK WITH THE GROW

If you only got 18 inches in height maybe you should re think this. You are going to need more height for that kind of wattage.
Unless you used a screen (scrog) and kept them real close, flowered with t5's that may work in that space.