biathlonfrenzy

Hi, I am currently purchasing new skate skis and boots.
I was just wondering what is the optimal height my skis should be. Previously I had 177 stiff and wanted to know if i should re order that size or get new ones.
I am 5'6.5'' without ski boots on and weigh 120lbs. I race nationally.
I am getting Fisher carbonlite skis and this is the only model i am able to get since it is under warranty so i dont want suggestions on other models.
I am also getting ski boots under warranty and wondered if anyone had suggestions on what to get. They would have to be salomon boots. And again I race nationally, so something pretty good quality.

Thanks for the help!