Relying on the 'clock tower' makes no sense
To completely bypass the fact that it's not a TOWER of any kind, let's think about this.
Why would they have to rely on the "10:04 pm" lightning strike, when they know there's going to be a lightning storm that night?
Couldn't Doc make some kind of system to simply harness the storm in some way, to LURE IN the lightning bolts, so they don't have to rely on ONE SPECIFIC lightning bolt, but they could actually have constant lightning at their disposal, or at least time-independent activation of the time machine?
Couldn't Doc ALTER the design so the car doesn't have to be going 88 mph for it to time travel? I mean, WHAT rule forces that weird limitation anyway? Why 88 mph, why movement?
I mean, if old Benjamin Franklin was able to get lightning lured into his kite and key system, surely 1955 Doc could devise something more sophisticated.
Also, couldn't doc create some kind of 'lightning container' so he can just use that power at will at any point he wants?
Also also, all this lightning stuff should make Doc think using a hard-to-get, rare substance like radioactive plutonium might be a bad idea, and he could research for powerful alternatives OR make the energy requirements somehow much smaller? Perhaps he could finally stumple upon Nikola Tesla's inventions and deservedly trash that business cruelty engineer and businessman edison's picture and replace it with the ACTUAL INVENTOR and TRUE GENIUS called 'Nikola Tesla'.
In any case, it's not the clock tower that's important - if the clock tower can lure in lightning, SURELY other things should be able to, too. Just like in 'The Terminator (1984)', Sarah or John are NOT the important things, it's the INFORMATION on how to destroy the machines and how to be a leader that can inspire people to 'smash those metal mrfrkgrs', that's important - movies always stick to one rail when it's clear that it's not the most important thing or the only way.
Clock Tower lightning bolt is NOT the only possible lightning bolt in that thunderstorm. It's a damn THUNDERSTORM, and he's supposed to be an INVENTOR - why couldn't he easily invent OTHER, more effective, activatable(?)-at-will, super-efficient and better than clock tower lightning rods that would lure in the lightning, even if he has to install them near the clock tower?
Why is this really hare-brained stupidity his plan, when he should've utilized the knowledge of a lightning storm in a MORE BROAD WAY instead of just trying to utilize ONE known lightning bolt? Doc should have some idea just HOW MANY lightning bolts happen in a 'terrible lightning storm', he should have a way to HARNESS those lightning bolts at will.
Heck, he could build a much higher and better 'lightning rod' into the DeLorean that DIRECTLY lures in lightning from the storm! That way, all they would have to do is to drive around the storm area 88 mph and at some point, the lightning would come.
No need for such an IMPOSSIBLE timing just to harness one SPECIFIC clock tower bolt. And yes, it IS impossible timing, when you do the math - how many meters will an object move in a QUARTER of a second if it's going 88 miles per hour.. it's mind-boggling (I forgot the details, but I did do the math, and it's QUITE A DISTANCE!!)..
There's NO WAY even in modern times anyone could get that kind of timing SO perfect a 'lightning-speed bolt' would enter the DeLorean's systems.
The timing of the hook touching the cable and the timing of the bolt - to synchronize these is just impossible without enormous luck and coincidence. Even if the wire remains electrified for a full second, I would still bet against it, no matter how meticulously you plan it. Only if you have some synchronized robots doing the driving and no wind resistance and so on, and you have calculated it as precisely as possible, it could MAYBE happen, but I doubt it would still be unfeasible and improbable because of the fluctuation of the acceleration and all.
The car can travel SUCH a long distance in one second, that if you hit the wrong second, it just won't work. Also, the wire would not be electrified for a full second, so basically even if the hook hits the wrong quarter of a second, it wouldn't work.
This improbability should've made Doc devise an alternate plan. You have a huge thunderstorm, surely you could utilize that fact more intelligently as a genius inventor.
Or you could decide to not steal plutonium in the future = problem solved. But whatever, movie's gotta movie, I guess.