My first thought was that the spring center bolt head was not seating into the hole in the front crossmember.
Looking from here, you've probably done that bit correctly.

What may be happening - especially if you've removed a couple of spring leafs in an attempt to either get lower or soften up the ride - is that your spring U-bolt, pad setup is not reaching far enough up into the channel to keep the spring pack seated against the underside of the crossmember.

Some of the U-bolt, spring pad setups come in two pieces, but most come in one piece with a step built in.
The stepped part goes on top and shoves the spring pack up against the underside of the crossmember.

Make sure as well that the spring pad is not bottoming out on the lower flanges of the crossmember.
That will keep the spring from going up against the underside of the crossmember and allow the spring center bolt to drop out of the locating hole.

It doesn't take much to allow the spring center bolt to drop out of the locating hole.
Re-pro front crossmembers - and probably the stockers as well - are 3/16" thick.
When the center bolt is where it's supposed to be, the top of it will be flush with the top of the crossmember.

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Your alignment sounds reasonable.
The tire wear on the outer edges may be due to underinflation or zinging around the corners.
(My wife used to enjoy bombing around the freeway on-ramps - almost always a right turn - and the left front tire wore on the sides worse than the others. Took me a while to figure that out.)

Fwiw - I have 32 roadster with 195/70R-14 front tires and run 30# pressure.
The rear tires - 285/70R-15 passenger tires run 20# pressure.
All tires BF Goodrich fwiw.

Those are the right pressures for the 32 which weighs 2400#.
It runs a 462" Buick engine and T-400 trans and has a top and four point roll bar.

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The guys are right, you do need a panhard bar.
Don't install one just to mask a spring center bolt problem.
Get that squared away first and then add the panhard bar.
The steering will be much more accurate with a panhard.