It took a LONG time, even with the dremel…
The hard part was accuracy.
When you get too the honeycomb section… your drilling empty space, and some material.
Sounds easy, but lack of material, lack of constant pressure, lack of control, while its super thin…
Not fun.
Maybe swap over to a hand file when you get to the finer part of ratting out the new grip. 
More control over how much you’re removing.
I did that as well… still less control, and slow going…
Perfection takes time. Patience young padawan 
My advise for today was, for a hairline crack, try filling with some superglue.
Its very liquidy and runny, most likely to run into the crack and fill it.
I’ve done that, applied by hand with glove, and rubbed it in.
I’ll let it dry tonight, light sand 2morrow and repaint…
fingers crossed…
If you need to fill deeper cracks Superglue Gel works well.
Just don’t trowel it on too thick… needs longer to cure too. 
Sanded down to what felt smooth, and resprayed.
It looks worse.
Patch lines, from where the superglue is.
Thats it, its official, im starting again…
i’ll order another, and see if he can print with better material and thicker walls…
This’ll do, as a temp, until the other arrives…
Try using baking soda to fill. Apply super glue, then baking soda then top it with superglue. Sets like a rock. Dress it and finish as desired.