Bicycle Mechanics - first time wheel build, someone look over my homework please?

so i plan on building my first wheelset. i found the specs on the spocalc excel sheet on sheldonbrown.com - i do get the general idea but would like to make sure i am reading everything correctly. does it make sense that i would need three different lengths of spokes for the wheelset? i am pretty sure i can purchase the spokes in the quantities that i need, but a lot of places sell them in packs of 100 :eek:

inputting the data that i think correct, i obtain:

289mm for the front wheel *
288 and 286mm " " rear wheel *

rims are ambrosio focus FCS 28. i see them in spocalc.xls (sheldonbrown.com) ERD is 590.0mm with 0mm offset. cool.

hubs are contemporary campagnolo chorus. i suppose these are the "Campagnolo Record OS" and "Campagnolo Record, Chorus, Daytona OS" on that spocalc.xls. i am looking at the correct line, yes?

* chosing as spokes "DT Competition 2.0/1.8" and a 3x lacing pattern (32 spokes) with "DT Messing 2.0 / 12mm" nipples on the dtswiss.com calculator.
quite obviously the lacing pattern will change the spoke lengths. but does the type of spoke change the spoke length? spocalc.xls doesn't ask for what type of spoke or nipple.

thanks! if you could confirm that i'm looking at the correct measurements for the hubs or prevent me from purchasing the wrong spokes... :D:o

Recently I used the DT Swiss calculator for a new build. I did notice that slightly shorter lengths are calculated for their Revolution spokes (2.0-1.5-2.0) as compared to their Competition spokes. I assume that this is to compensate for spoke stretch. I've used Revolutions on several of my wheels and they do stretch, more than 1 mm on the driveside rear. This is because they are so skinny in the middle.
And yes, it's normal to need three lengths, and always round down when selecting lengths. This is especially important for the driveside rear spokes due to their higher tension.


Al

ok. thank you. the spocalc.xls thing is straightforward enough but i figured i could still mess up by choosing the wrong hub in the list or some such. and when i am sure of the spoke pattern i'll definitely double check with the dtswiss.com calculator for the revolution or competition spokes...