the old standard of measuring that's still dominant is the length of the seattube from the center of the bottom bracket to either the top of the seatube (way old school-still in use sometimes) or the center of the toptube. nowadays with sloping top tubes of all sort this measurement is arguably less important than top tube length. the top tube defines to some extent how stretched out you'll be on a bike and should probably be the first measurement you look at. top tubes are measured from the center of the seat tube to the center of the headtube.
nightfall a 61cm is gonna be too big. i'm 5'10" and ride 54-56cm frames. you could probably get away with a 57-58cm but i doubt bigger would work well. the best thing to do is ride a bunch of bikes and see what feels good.