[sallen15]

Welcome to YT! There are so many great people here filled with info!

My Lucy is also about 4 months (17 weeks) and she weighs 3 pounds 12 ounces, according to the growth chart she will be about 6 pounds full-grown.
Typically to figure out the adult weight of your Yorkie you double their weight at 12 weeks of age.

As far as crates go, I use a wire one for Lucy we have to crate her all day so we attached a waterbottle to the side of the wire crate, plus a tray at the bottom pulls out if there are any accidents for easy clean-up. I think I also have that plastic crate you are talking about, we tried to get lucy to sleep in one of those, but she didn't like it, barked and cried when she was in it. So needless to say it's just sitting in the basement collecting dust.