Bit of a bump, but I’ve been thinking about Lightning Fryer lately, and I think I may have some alternate suggestions regarding its balancing.
The changes I’m proposing here were made with the current chaining system in mind, and with the assumption that this system will stay in the game (which may very well not be the case). So let’s talk about that first.
The way chaining works right now is based on the bolt bouncing off of an enemy at just the right angle to hit another enemy. Which requires either precise aiming or luck, and sometimes can’t occur at all. One way to overcome this is to just have more bolts (the more bolts you have, the higher the odds that one will bounce successfully). And so, bombers are generally more effective than fighters when it comes to chaining alone.
Another thing to consider is @1galbatorix1’s initial idea of bosses taking the full DPS due to chaining. This may end up being problematic to balance, especially since the proposed 18000 DPS is quite a lot for an instant-hit auto-targered weapon (though it’d be more acceptable if DPS was lowered to around 16000, provided that chaining would also be made easier to make sure that that 16000 DPS can be reached on regular waves as well).
And so, I’d like to suggest another power progression for the Lightning Fryer, one that focuses mainly on gaining more bolts more quickly. One bolt on 
0-3, two on 4-7, three on 8-10, and finally four on 20.
To avoid massive jumps in damage output, transitions that increase the number of bolts would have to weaken the individual bolts as well (just like the current transition to 6 does). So with this approach, we’d sacrafice single-hit damage in exchange for spreading out the still rising overall damage output across more enemies.
With such a progression, bombers would reach 6 bolts at 16, and 4 bolts at 8 (4 levels earlier than currently).
I considered several versions, and I think this is the best one I’ve come up with:
In my opinion, 10-12k DPS is the lower limit of what could be considered useful. Bosses would still take a pretty long time, but wouldn’t be tedious to battle. The issue is that with such values, we reach a maximum DPS of over 22k. Which is a lot.
That being said, I think that if the current chaining system remains largely unchanged, it wouldn’t really be overkill. It’s currently quite rare to reach the chaining limit, and even if it is reached, it’s for a very short amount of time. Alternatively, the system could be made a bit more forgiving but with reduced damage (via reducing the max amount of chained enemies and/or damage dealt to each next enemy in the chain).
As far as problem #3 (bolt width not being consistent with damage) is concerned, it should be simple enough to fix. Just make the bolt’s thickness tied directly to its damage.