I soak mine thoroughly and then squeeze out the entire stack of them before putting them in. Any less and I end up with dried out wipes that need wetting. Any more and I end up with the possibility of mold, or at the least, obnoxiously wet wipes.
I soak the insert thingy, then put the wipes in dry. Then I pour about a cup of my wipes solution over them. You don't have to be precise because a few hours later the moisture is all distributed evenly. And I used to have a mold problem, but I started adding 1/4c vinegar to 1 gallon of water and now I never get mold. Nor have we had a recurrence of The Yeast Rash From Hell.
Re: using the wipes warmer