Hmm, I cant find any 17mm adaptors on the Pro-line site. Anyway, I had some OFNA 17mm adaptors once, and they just slid onto the axle and were secured with a cross pin and set screw to hold it in. The 23mm Pro-line adaptors I had just had the slot cut into the back to accept the cross pin, then the nyloc nut went in the front to bolt it into place.
The UE cvds are a bit silly like the Tamiya stub axles which were/are splined & have a splined hex. All I can suggest is the 14-17mm adaptor hex which goes over the top of the stock 14mm hex.
That, or any chance of finding some off-set rims with a 14mm hex?....