How many hours of light while vegging & should i switch to a 600 from a flourescent?

Hi Guys .. Jst another quick question & any aswers wld b greatly appreciated, a guy told me nt to bother with the 18 hours of light & 6 hours of darkness .. Hes tried to assure me tht i should b able to leave the propogator light on for 24 hours a day without turning it off, its 6 small motavation plants .. 3 weeks old & very well rooted, also wen should i change to a 600?? Toke on Guys

It was found in a study (Iv no links, sorry) that 20 hours of light with 4 hours of darkness produced the most yield in the end...

Hope this helps

EDIT: I use a 400w MH to veg and a 600w HPS to flower, so Id be a little biased and couldnt help with your other question...but a 600w HPS will veg just fine, just not too close

any ideas on the distance from the tops of the plants?

i use 1k hps and a 1kmh simultaneously and i have the light 16 inches. with a 600 id try to stay no farther than 12in