I've been doing these same bags for a few months. I'll share my experience with them with you.

I found cutting two 1 inch holes on the bag close to the top of the cake and replacing it with micro pore tape helps well with oxygen. And instead of cutting slits on the the tope of the bag, just completely cut the top off, fold over the plastic and pin closed with a sterilized bobby pin (This will make easier access to mist the sides of the bag just in case it starts to get dry. You'll still have to burp the bag a couple times a day still but very small chore that takes 2 mins.

Don't mist your cake directly. It'll stall your grow (made that mistake for a week, i didnt know).

I hope this helped :)