I can't comment on the AS4's as I've not used them, but I will offer some feedback regarding the alignment process. Have a look at this
Make sure that your servicing agent is using alignment specs for the C7 FE6/FE7 suspension options as a basis to start with. These are specific to the GS/Z06 and the GS/Z06 with the Z07 package. FE3 and FE4 specs are for the base Stingray and Stingray with Z51 option and should not be applied to wide body C7's. You'd be surprised how many dealers don't know the difference. Also, make absolutely sure that your servicing agent has the rear caster adapter and angle gauge needed for checking/setting the rear caster and that they know how to use it. This is the starting point for a proper alignment on a C7 and, unless the rear caster is set within factory spec, the rest of the alignment will be off.
The primary reason that the inside edges of all 4 tires are worn is because the factory alignment is too aggressive, typical for GS and Z06 C7's. It's usually a result of excessive negative camber and toe settings, both front and rear. Theoretically, the closer you can get to "zero", for camber and toe, the more "street friendly" your alignment will be. Although it's not possible to achieve "zero" settings on FE6/FE7 suspensions, you can get close. See the included alignment spec sheet for the settings applied to my GS which has 18,000 kl's on it with perfectly even, measured wear on all 4 tires. Also note that the rear caster spec is penned in at the bottom. That's because most, if not all, dealer/specialist alignment equipment does not measure rear caster, it must be done manually using the adaptor and angle gauge.
I can't stress enough the importance of the rear caster setting. Finding a qualified alignment specialist that has the adaptor and angle gauge is imperative to achieving a proper "street friendly" alignment, or any alignment, on a wide body C7. That, combined with the less aggressive camber and toe settings, will give you the increased tire life you're looking for. Without these things you'll probably be back in the same boat in 20-25 thousand kilometers or less.
Hope this helps.