On 90% of the cars these days it seems only the toe is adjustable. I must have done a couple dozen DIY alignments with a tape measure over the years and I can always get the steering wheel on dead center with no pull or wandering to one side. It may take 2 hours of trial and error, but that is still better than taking it to a shop and waiting or dropping it off.
You do realize that the upper tower mounts is a typical adjustment point?
Back to topic, instead of counting threads, measure how far out the outer TRE stud sits from a point on the inner TRE. Since the typical outer TRE is the female and inner TRE threaded, make a mark on the inner TRE, not to know how many turns to thread it, but up further on the inner TRE to measure to the stud on the outer TRE.
That's just to get it close to drive to an alignment shop.
Can you do without that? Yes, if it seems to track and steer well you can wait a while, but probably not a good idea unless you're going to replace your tires soon and get an alignment done at that time. Otherwise, odds are you're going to put excessive wear on the tires and possibly suffer poor handling too. If you're not the primary driver of the vehicle so you are unfamiliar with how it handles, I wouldn't even consider guesstimating if it handles the same for someone else's vehicle, though of course if the old TREs are worn, it might feel a little less vague with new ones.
This car is kind of a beater...
On the other hand, if it is just squeaking without excessive play, and assuming it's a sealed unit (no grease zerk), you might see if you can get a grease needle in there to add some grease, or even a tiny bit of oil alone if there is almost no play. If that doesn't last long term, you're out nothing but the few minutes to do it.