Hi! We had Disney Cosmetology do my hair, and that of my MOH, and they did a FANTASTIC job! They were well worth the $95 I spent (plus $30 for nails & $30 for tip - $15 per cosmetologist). Oh, and for the MOH, she only got her hair done. You may want to consider just paying the $50 for her hair, and letting her do her own makeup, since most women know how to put on makeup, but it's the updo that would be a challenge to create.
I didn't do a trial run - it wasn't worth it for me. I know that they are professionals, and I knew that they would do a fantastic job - and they did!
I rarely wear makeup, so I was worried about it looking natural enough, but they really listened to what I wanted for makeup. For hair, I was so vague - I knew that I wanted it up, with curls, and I knew that I wanted tendrils coming down along each side of my face, but other than that, I had no idea. But I trusted them, and they made magic with my hair and my MOH's.
Another thing to realize is that they come so early that if you do happen to dislike what they've done, they have time to change it. They arrived at 8 am for our 12 noon ceremony, so if I had been uphappy with the updo or makeup, there was plenty of time to change. Just another reason why I found the trial run unnecessary. Another was that you're not guaranteed to have the same person doing your hair the day before & the day of the wedding, so there's no guarantee that the cosmetologist will be the same one and know what you want from them on your wedding day.
Cheers!
Heather W