Vacuum line sizes

[Roa, Greg]

Hello all,
I am going to start replacing vacuum lines on my 86' 4kq as they are old,
original ones.  I was planning on going to the local flaps, and picking up
various sizes of vacuum line hoses.  What common sizes should I pick up?  I
was going to measure the old ones, but most of them are old and brittle, and
not in the greatest shape.  Several are in a condition where I don't know if
they will survive being pulled apart and put back together.  Any ideas from
people who have changed theirs?  Amounts you used?

Also, I suppose that this is related to my likely leaky vacuum lines, but
when I am driving at highway speeds, I can often feel a mild change in
speed.  It will cycle every few seconds, and feels like I am driving in
gusts of wind.  The car will just feel like it loses a bit of power for a
second or two.  This the vacuum problem, or something different like the o2
sensor?

Thanks everyone!

Greg Roa
Cincinnati, OH
86' 4kcsq
93 90CS
83' 944