Jim, love your tow bar! I made one from 2 bars, a regular Bug bar and a Super Beetle bar(which is narrower to start and the right width for my Vintage Spyder). Mine got lengthened about 18-24 inches also and got lowered about 1.5" to clear the bodywork.
Ted, get the bar made up first, then hold it level to get your hitch height, then buy a riser or drop piece for your receiver(I use an 1.25" receiver, Class I, this is all I need) to get the correct height.
I ended up running a trailer wiring extension through the car permanently, and use the car's taillights when towing. Back plugs into tail when needed, front is coiled up and comes out the hood to plug into tow vehicle. I know I should put a "car in tow" sign on but I always forget. Besides, it's registered and insured so.....