OK I wanted to update this thread from what I said I was going to do above.
Since this post I have made some changes. Instead of the zj front steering, I opted to the Currie sync, but that didn't make any difference for the alignment. And now I have 33 inch tires.
So I did the alignment as was directed at the beginning of this post. I actually adjusted it. Then I put the tires on, and tied up some other loose ends. I then drove the TJ around the block and parked it in the same exact spot, and with the tires on, I measured with the Longacre toe plates, and it was right on the money.
So based on this I think you can do it either way, and it will be same or really really close. I will probably use the toe plates, so I don't have to lift the Jeep and pull the tires, but If they are already off, I will probably do it the other way, but I am pretty comfortable with either way.
I will say if you had the toe plates you could just check it really quick like during an oil change after a good wheeling trip.
Not trying to sell you anything, but just in case you are interested here are the exact plates I used.
https://www.amazon.com/gp/product/B000VAOHB2/?tag=wranglerorg-20
Looks like they are $64 now, I paid 58 a few months ago. I would still buy them at $64
Cheers