I am working up a tech tree line and I am on the T8. The crew in the T8, I am planning on moving to the T9 and then finally the T10. I have a bunch of crew books I could use to dump a bunch of XP to the crew and get a few perks.

My question is: If I do that now and give them more perks, does that mean it will take more XP to retrain them to a new tank(s), vs if they had less perks? Trying to decide if it’s better to use my crew books now or wait until they are in the T10.

Thanks!