you're doing good.
if you want to make it like bally did it so you'd match bally documentation, below is an example of a reel wiper wiring diagram used on the 742A-118, 742A-2G and a few other models. They are oddball machines with operator adjustable payback percentage.
1] the columns of rivets marked 1-9 are the slot depths, where 9 is the deepest slot. The gotcha ...
2] the diagram is drawn looking at the wiring side, so the wiper arm represented by the dashed line can only move left. It's impossible for the wiper contacts to sit on the rightmost 4 columns of rivets on the diagram.
3] the way the wiper fingers are connected together is indicated by the sets of joined arrows to the right of the rivet columns. You'd want to redraw those like your game has.
4] the tape symbols corresponding to the slot depths are above the rivet columns. It's not always true that each symbol maps to only one column depth. On multiple line games, games with mystery pays, or games with scatter pays, a payline symbol may index into different slot depths depending on what symbol was above/below it on the tape.
so the J-M rivet columns in your picture are not used, and columns I-A are slot depths 1-9. In this case, you don't use depth 9 either.
you could load the diagram into a graphics program and erase the existing information to create a blank template, then fill in the wiring of your game. For the wire ids, you can look at the payout counter diagram and use those ... bally tended to use the same id's for the payouts (e.g. the wire on the 2 trace is 13, the 5 trace is 15, etc). If the same color wire was used between reels ... but is not the same wire connecting to multiple reels ... then the second use of the wire color would be something like 13-1)
742A afaik have the connections to the payout counter coming from the reel 1 wiper board, so some of the wires on the reel 1 board are going thru the plug connections to your m-645-96 board.
recreating the reel wiper wiring diagram is a bit of work, but it's the only way to determine how the game paid and how much it paid when you don't have all the paperwork or the glass ... or if it's a custom machine or just something assembled from random parts.
having said all that, if the goal is to make a working machine with bally original glass (rather than producing a custom glass), then you're probably starting with finding a glass to stick in the game that matches pays your payout counter disc supports (or replace the payout counter disc also), then you rewire the reels and make tapes so the index discs you have will produce what the glass says.
you may wind up using multiple slot depths for the same symbol to adjust the payback percentage or hit frequency, or you can do the mystery pay approach where the game makes a payout that is not on the glass
finally, if you want to figure out how the 742A-2G machine and it's variable payback worked, I think I have the schematic and some other docs for it ... but not the payout counter diagram.