So I just discovered that my school has a 4x5 enlarger, which I am pumped about. The enlarger we've got has an Omega 45 condenser head (and two el-nikkors to boot). Problem is, where the hell does the neg carrier go? I only see a single bellows. Is there some piece of the enlarger missing that I'm too stupid to realize or just somewhere I hadn't thought to put the neg holder? Also, the lenses are 105mm and 135mm. I've never enlarged 4x5 before...will these be sufficient focal lengths?