I did my friends '68 Camaro steering wheel using Eastmans PC7 two part epoxy system. I took an old coarse file and broke it into about 3" long pieces, (Easier to handle), and cut the cracks into "Vs" then filled the cracks about 3/4" wider than the crack and slightly larger in diameter than the wheel grip. After the PC7 cured I first filed the epoxy down the switched to sandpaper and finished with a 400 grit paper.
After being painted gloss black, it looked like brand new.
I do remember wondering why I couldn't use JB Weld instead as is seemed to have the same consistancy and performance.
Rezman