Here you go. This is a 6-digit display (26 resistors). 7-digit will have 28-30 resistors depending if it's a Bally with comma circuitry or not. Ignore the jumper wire on this one, obviously that has ways of looking cleaner as in a previous picture I posted.
What I found works is using ammo pack style resistors (tape and reel). Keep them in the tape, snip one side of them leaving 1/8th to 3/16th of an inch lead length. Then they're all handy to point-solder one side of the resistor into place. Just add a bit of solder to pad of one side of each resistor you're doing, then hold the resistors (still on the tape) in one hand & solder the short lead of each resistor to the pads you had added solder to. After soldering each one, pull down on the tape and it'll release the resistor. What you'll end up with is one side of like 6x or 7x resistors of that value soldered on the board with a long lead hanging down. Then just press the long lead into the opposite pad (directly in-line with the pad that was soldered), snip the lead over-top of the pad & solder. You can do those steps for all 6-7x resistors of a value at once. Makes it quicker not dealing with individual resistors and finding a way to be more efficient getting them soldered in. You then just have the 7x segment driver transistors to fully desolder & replace.
Here's the topside of the board -- really no different from stock, but a few resistors and CR1/VR1 diode cut off. J1 PIN #1 pulled.
I'm not saying soldering in parallel is for everyone.. or even that the conversion kits are for everyone, but I think the end result either way doesn't look too bad. Just as I said, you probably want to practice desoldering on a junkier board if you *plan* to replace all the components, jut to see how it goes and/or perfect technique.