FIRST off- Dads really should get more involved with the boys, they have the same equipment. And boys are generally harder to potty train. They teach them how to hold it and shake it, etc, and to put the lid down for the ladies.
Secondly, you took a step backward to the diaper.
But you are right it's not good or healthy to hold it. Did you Know urine is STERILE when it leaves the body? That's right, no germs. It is not like poop, but remember it's just poop and pee, we wash up no biggie.And so here is some advice:
Make it FUN! My son took appx 1 yr. We hung construction paper in the bathgroom, every time he tried he got a sticker (his choice, and let him pick several kinds when you buy them., I rememebr it was this time of the year too, we had turkey stickers :D at first.) If he does pee or poop, big WOOHOO pipi dance or poopoo dance! TWO stickers! Three, who cares!? but be consistent.
You can put food coloring in the potty (yellow and blue make green) or cheerios (target practice)but here is good boy advice because many kids are scared of the big potty: SIT HIM ON THERE BACKWARDS, that's right, facing the wall. For some reason, they feel more in control. Trust me, they'll stand when they are ready. Let HIM flush (good time to teach only pipi and poopy goes down the potty, because trust me, they will put hair clips etc down there later) and holler BYE BYE PIPI! GOOD JOB, Davey (his name of course)!
By the time we were done, there were MANY. like 6 or 7 sheets with stickers. They were hung in his room till he was like 5.
And if you need a nightime pull up, who cares? sounds like you don't though. Just be careful not to get too into the germy thing, they do that enough at preschool. Make light of his poop and pee, it's part of him so it's all good. aND REMEMEBR TO TELL HIM, oh I AM SO GLAD YOU ARE LEARNING THIS SO YOU CAN HELP ME POTTY TRAIN yr BROTHER IN A FEW YEARS.
bUT HANG IN THERE, AND EXPECT MISTAKES. it is a long process, mistakes are normal. But you gotta relax, so he can, ok? Don't worry, he will have it all figgered out by kindergarten, promise. btw, you are doing the right thing by taking him every 20-30 minutes. Reward him extra when he TELLS YOU he needs to go, part of this is "listening to our bodies", and his identifying the need to urinate is the key. (Girls are better at this, big surprise huh?!:D) GOOD LUCK!