Primer testing for lowest ES

[Alpheus]

How do you guys test primers to get the lowest ES? I typically pick a primer-powder-bullet combination and shoot a ladder, then some test groups to confirm. Would shooting a series of groups with the same powder charge and bullet but different primers over a chrony be a good way to find a low ES, then doing a ladder with the best combo?
I know the ES will change with different powder charges, but shooting a ladder for each combo is going to take a lot of time and components. I've got 2 brands of primers, 2 powders and 4 different bullets to start testing with, doing a ladder for each permutation is going to take too long.
Any thoughts..?

 

[Ganderite]

For match ammo I use match primers. Either CCI or Federal. Whichever I happen to have on hand.

On one occasion I could not find 40,000 match primers of the same lot #, so I switched to stand Winchester. ES was the same as match, but velocity was 25fps faster with same powder charge.

Only time I would consider testing primers in an application was if I was going to load ball powder. Then i would compare match primers to Winchester.