I have no grief with any scale assigned to any TIE model kit, since it is all "made up". My personal 'TIE journey' has led me to specific choices, as is with most modelers playing in this particular 'sandbox'. In short, my findings are logical but subjective and follow my own 'paradigm' for the TIE fighter concept.
Basic size comparisons of the older kits illustrates just how variable things may be. Consider the below measurements for the 'standard' TIE fighter (I include the First Order 'Special Forces' TIE just as a curiosity...)
KIT ..................Kit Wing Height (mm)....Scale Height if 1/48......AMT Differential
AMT(old)...................151...................................23.779 ft...................................----
Fine Molds (48)......157...................................24.724 ft...................................96%
Revell (85-1875)....185...................................29.133 ft...................................81%
Revell (FO/Sf).........177...................................27.874 ft...................................85%
The Fine Molds is a very nice depiction (even has a tiny Sherman bogie to glue on the rear!) with accurate and complete detailing. The old AMT kit is almost as good, being very accurate as well, especially with the new retooled wings of the correct shape. The FM kit is only 4% larger, with the cockpit ball being almost the exact match for the AMT kit. Both kits have the fictional cockpits, neither really accurate to the ANH cockpit sets, but the included 1/48 scale pilots fit nicely within the cockpit envelope, which just feeds my 1/48 constant scale collection motivation & so my adoption as my standard 1/48 scale "size" for a TIE.
The Revell 85-1875 'snap & play' kit has a pilot that matches the proportions of both the AMT and FM kit, with the Revell cockpit being a near exact (if larger) copy of the AMT cockpit. All three kits are good models of a standard TIE and can be recommended as good choices. None are of the same degree of accuracy as the new AMT "1/32" kit, however, from what I've seen on the forums so far. Understandable, given it is new production with extensive research put into its design.
A couple of footnotes about my 'journey', if I may. Consistent and with an exact 'viewport' diameter match to the AMT kit is the Estes TIE X-1 model. The Estes kit is essentially a detailed X-1 that is engineered to accept a rocket engine up the "whazzoo". It is injection molded and has separate detail parts and an opaque viewport, easily replaced with one from the AMT kit. The engine section may be a bit out of proportion because it is sized for the engine, however it is not off by much. A rocket tube is inserted into the removable viewport so the TIE 'wings' serve as the rocket's fins (not all that well apparently, since it is said to be a poor flyer... probably why it was on sale at 'K&B Toys' discount outlet!)
MPC released an TIE Interceptor kit that is the same cockpit size as the AMT kit, which Round 2 took advantage of to upgrade as a reissue, combining the more detailed AMT kit parts with the Interceptor 'wings' - an idea I'd already realized as a kit-bash with the original kits. Unfortunately, the molding on the TIE/i wings isn't quite as good as the AMT parts, but it still works nicely.
So, I have taken a modeling path that gives me two (three?) variants of the 'standard' TIE fighter, an X-1 and TIE/i and, a FO TIE/sf from the Revell kit if I assume it is a larger craft to accommodate enlarged volume for a two-man crew, hyperdrive engines and a ventral gun turret. Additionally, converting the old MPC X-1 kit to a TIE bomber works out to be 'in scale' as well. Other possible projects are a Striker and TIE/d (droid?) scratch/conversions... guess the 'journey' isn't over yet!