I thought of something else that you can do, but it is more involved, and shouldn't be attempted if you are unsure of your skills.
If you have an old Ukulele tuner lying around, you can drill a 1/2" diameter hole in a 2" x 2" x 3/4" block of wood on the top, going down through to the bottom. Then drill another hole in the side of the block ( 3/4" side ) to allow the tuner post to sit in the hole that was drilled vertically.
Now attach the tuner to the block on the side, and make sure the tuning post is protruding into the vertical hole and that the button is in a place where you can turn it without binding on something.
Next you wanna get a small piece of wood about 1/16" thick by 1/4" by 1/4" ( sometimes called a graft or a cleat ) .
Drill a small 1/16" hole through this small square wood.
Drill another 1/16" hole right through the crack in your ukulele.
Next, take a piece of fishing line about 1' long, and put it into the tuner post and tie a knot so that both ends of the string are coming out of the bottom of the little tuner block of wood.
What you want to do is put the fishing line into the hole in the crack in the Ukulele, an then bring it out of the sound hole. Pull tight and the tuner block will snug up to the Ukulele itself.Then put the fishing line through the tiny patch wood ( the one that was 1/16"x 1/4"x 1/4" ) and tie a bigger knot so the patch wood will not come off.
Finally you want to rub a drop of Titebond Original wood glue on the patch wood ( the side that will touch the inside of the crack) and then just turn the tuner and reel in the patch block until it is snugly against the crack on the inside. In 30 min to 1 hour, the glue will be dry, and the fishing line can be cut and retrived from inside your ukulele.
The patch block bonds to the inside of the crack to keep it from ever widening.
After the above is completed, putty the hole with wood putty and then do the superglue trick from the post above.
The purpose of the tuner block is that it makes like a clamp to hold the patch block in place where as most or all other clamps wouldn't be able to hold it.
If this is confusing, please let me know.
DISCLAIMER:
I have never attempted this maneuver, However it was explained to me in detail from my Ukulele building teacher Mike Chock of Hana Lima Ia. Again, if you think that you are gonna mess your Ukulele up more by trying this DON'T DO IT.
Hope this helps too.
Aloha
Bob