I just had a nice phone conversation with Bill at GPA, therein he essentially talked me out of sending the drivers in and "wasting my money". I learned that a vast majority of drivers that pass through GPA need no regaussing, and unless I have reason to suspect otherwise (I don't), mine are no exception. I also learned that my 802-Cs would not accept the GPA radial waveguide as the pole piece would have to be changed. Bill went on to explain that the tangerines made only a tiny improvement in the high frequencies, and would not improve the directivity (or enlarge the "sweet spot") as I had first believed it would.
I got a good giggle out of the notion that you were going to have tangerines installed in an annular phased Altec driver.

We have discussed phase plugs here ad nauseum in the past. Common knowledge among seasoned Altec enthusiasts is that the tangerine was a cost cutting measure. It's a cheap, injection molded piece of plastic versus a precision machined piece of steel, pennies to produce versus tens of dollars for the metal version.

What Bill may not have told you since you have not mentioned it is that the tangerine pretty much destroys the small format drivers' ability to play well in the 500 - 800 hz range. Kinda sad because the alnico drivers that came with tangerines also featured other changes which were genuine improvements. Most notably the 1 piece cast steel magnetic return pot which offers a more uniform magnetic circuit than the welded pipe and plate construction of the annular phased drivers.

Acoustically, the biggest improvement it offers is that you can wring a few more db out of it before you encounter driver cry in a high output pro application.

Mythically, tangerine drivers are supremely valuable, and will outperform any other driver at any cost which makes them easily inserted into the uninformed.

The small format drivers will only require re-magging if they have been shocked/dropped significantly(enough to shift the pole piece usually), or if you have taken the motor assembly apart.