For me it depends on how you shoot. If you twist turrets, then the length doesn't really matter. 22 to 24 would more than get it done, and if you hand load, then "lost" velocity can be found. If you are a hold over shooter, then a longer barrel may be the ticket, as you'll want all the speed you can get, for less hold over.
Optimum length really doesn't exist, as each barrel length has its time. Once that time is calculated, a velocity can be determined, and loads developed to match. So, chop it to whatever feels best for you, and the rest can worked out.
R.