I've been where you are. It's really neat, huh?
Our lil kitten didn't go every time after eating, but most times. You needs to get a wet cotton ball (wet with warm water) and stimulate her by rubbing gently on her pee-pee and anus. Not on the tummy. You can rub the tummy, too! Just make sure to rub the other areas.
The poo will probably be runny cause all she's eating is milk (like a human baby).
I don't think I'd do an electric blanket only because of the fire hazard of leaving it on that long and if she were to try and chew it or something. What we did (vet recommended) is filled a cotton pillow case with uncooked rice, tied a knot in the pillow case, and then heated the whole thing in the microwave for five minutes (during each feeding). Then, after the feeding, we'd put the bag under a couple towels, put kitty on top, and put one more towel on kitty. You will have to judge how many towels to put on the bag, depending on how hot it is.
Also, please keep kitty in a locked container (a dog crate, etc.). You don't want kitty escaping and having another animal get to her or her getting in trouble and hurting herself. We learned this one the very hard way.
That's why we only have the one kitty now.