No reason to stick to a particular length of dipole... There is a
reason we use open wire instead of coax, and that is it works with any
length of antenna
some short length restrictions apply, bni, sar, ymmv, etc.
Put it up as long as you can, attach feedline, diddle tuner, and
go...
IF, and only if, you have problems tuning one band or another, then
shorten the dipole by 2% and try again...
Just do it... Don't think... And don't listen to me, what do I know!

denny / k8do