Apologies for not responding sooner. There are two types of 738s, ones with small TV screens (3745-3773) and ones with big TV screens (3701-3744 & 3774-3777). The ones with the big TV screens are the ones currently going through mods and not much is happening to them; those are taking 3-ish days and are happening so fast it's not worth tracking them in a spreadsheet that's only updated once a month. To track them, go to the thread jjl468 mentioned above.

Once the mods start on the planes with small TVs, I will track those. Of course, they'll also be tracked in the aforementioned thread as well.