You WILL be happier with a 600w.
Vegging plants for a long time in hydro is very difficult for a noob, especially running non-commercial strains that can't take much abuse. If you intend to get decent yield off ~4 plants, and just HAVE to run hydro, you will need to run large DWC units similar to waterfarms, like the ones weedhound built.
IMVHO.. start in soil and make yourself a mother plant to take clones off. Then switch to hydro when you can populate something like an ebb n flow with rooted clones for flowering.
Just fyi... hydro weed isn't in and of itself better quality. So make your style decision after informing yourself of all the options!