What grip do you use for your serve?
There are many people who use a kick serve everytime they hit a second serve, so in that case it wouldn't matter. But it's still probably better to use the same grip so you can use one as a surprise for your first serve, or change up with a slice or something
Almost every pro hits a kicker for there 2nd serve so thats pretty predictable. Although I hit all my serves with a continental I was just mentioning that. And there are pros who hit kickers with an eastern grip