Spray the smaller pan with cooking oil and lay crackers edge-to-edge along the bottom.
Melt the butter in a pan and stir in the milk.
Add the sugars and bring to a boil.
Stir in the graham cracker crumbs and cook for 5 minutes, stirring constantly.
Pour about half of the filling over your layer of crackers.
Make another layer of crackers in the same orientation as the first. Or not. I'm not standing over your shoulder judging you.
Pour the rest of the filling over your crackers.
Make a third layer of crackers on top.
Cover with cling wrap and put in the fridge to firm up.
To try and make something visually similar to a Kit Kat bar, I cut up the pan of crackers into sticks. The plan was to make the familiar three-bar Kit Kat candy bar. While I don't feel I was successful in doing so, I certainly don't want to discourage you from trying this yourself.
If you do choose the hard path, let the candy come to room temp before cutting into bars.
Now it's time to make the magic chocolate coating that tastes something like the chocolate you know, and something I can't describe as anything other than "candy bar."
Melt the chips together in a double boiler (or microwave) until all smooth and creamy. I don't have a double boiler, and I tend to botch melting chocolate in the microwave, so I used one pan set on top of another pan with a small amount of simmering water in the bottom pan.
The melting process will take some active participation on your part, as the butterscotch chips don't like to play friendly and need some coaxing to melt smoothly into the rest of the mixture.
If you decide to go the route of making the three-stick bar, do as follows. Otherwise, just pour the chocolate coating evenly over the top of the layers you made in Step 4! ah, that my friends, is the "easy way."
Cover a larger baking dish in plastic wrap. Pour in a layer of chocolate and allow to set.
Arrange the bars you cut apart in Step 5 on top of the chocolate layer.
Coat the bars in another layer of chocolate, making sure to cover the tops and sides.
Once they're set, break 'em up and see how you did!