I forgot, you are the leather guy 
Please look at the following album for steering cover and gear detailed pictures:
https://www.dropbox.com/sc/32pvcdetkiy4z5q/eswqAd6G4V
For gear, remove the knob by unscrewing it and then stitch the leather on it. If i recall correctly, the needle he used was a slightly round/bended one to allow this zig zag stitching on the corners. The zig zag pattern of the stitch is the beauty of cover which reflects the hand stitchedness 
Also, beneath the leather, bond was used so that the grip is tight and doesn't cause any swollen/loose patches in between where you touch steering the most for turns. As per the guy that did my car, This bond wouldn't harm the plastic in anyway and is removable if ever you want to get it off.
@tjkhattak As per your PM, FYI...