Let me be controversial: if you don't care about weight, a taller tappet (at least from the lobe to the pushrod seat) weighs more than the length deducted from the pushrod, but it makes the pushrod much more rigid. Even 1/2" is worth something.
If the pushrod is 10" OAL, and the inserted eds are 1/2" each (the tube is 9"), taking 1/2" off the length has the same effect as increasing the diameter about 1/16": 16.6%.

One of the "secrets" to the LS: high cam placement makes very short pushrods.