Will be adding 5mm spacers from motorsport-tech. While waiting for them to be made, I've been doing some measuring. By adding the spacer it would only allow 7 turns of the lug nut to secure it. I saw in another post that 5 turns is the minimum but I am not comfortable with that few. Read elsewhere on a performance site that lugs the size of the Jags, 12mm 1.5, requires 8 turns. I can remove the washer on the OEM nuts and achieve an additional 2+ turns. By doing this the lug nut extension is just shy of protruding out the back of the rim. Does anyone see a drawback to this reasoning? I would put never cease on the flat part of the nut that comes in contact with the rim to facilitate tightening.

 

Doing a little more research and found the Gorilla lug nuts for a Toyota Lexus should fit via their measurements and add 3mm to the depth of fastening. Going to go that route.

 

Be careful with those nuts, they may fit perfectly or they may not.
They are 21 mm hex not 19 mm like the Jag nuts so you will at least need a new/different socket, and depending on your wheel type/style and the wall thickness of your socket they may be a very tight squeeze to get a socket onto. Most times it will be OK but sometimes it can be tight.
I got some very similar, mag seat 12 x 1.5 with 21 mm hex, I think they were Toyota but they may have been Mitsubishi, and they were no good.
They seemed to go on all right but after a few miles I started to get rattles and knocking from the wheels which quickly got worse and worse and it was obvious that the nuts were coming loose no matter how hard I torqued them down, especially on the rear. I think it was because the barrels were too long and the end of each barrel was hitting up against the hub before the mag seat washer was tight against the wheel.
But with 5 mm spacers this should not be a problem for you.
Anyway, once you fit them be careful the first time you venture out and make sure you have a 21 mm socket and breaker bar in the car in case they come loose.

 

Thanks for the words of warning. I will definitely take your advice.