well, yellow is no longer a weakness for the green lanterns. or maybe since hal jordan came back they put that back in.
regardless...in my limited green lantern reading from the days of hal jordon, the color yellow has to come in contact with the creations from the ring. so...if someone had a yellow spacesuit on, he couldnt poke them with a sword he made out of the green lantern juice. i think it only affected contructs, not him at all.
then again, people might be able to argue the light from the yellow sun was all over him...but those people would be assholes.
the charging is no longer necessary either, i dont think, but he would have to change once every 24 hours (and chant something dumb) in order to restore full power. of course, every villian that wasnt clad in yellow tended to attack on hour 23 while hal jordan was on his way to recharge, thus making the story somewhat more thrilling. in theory.
edit: i should point out that both the recharging and the yellow weakness is a sign of a certain age of comics. there were tons of characters who were only useful for a very set period of time. Hourman, for instance...and i think Aquaman couldnt be out of water for very long either.