Slot Math Research

Hello all -

I have switched careers into the gaming sector within the past few months. I do have a math background and have been doing my research on how slots machines are designed & how results are computed. (A big thanks to Michael Shackleford for the Atkins model to give me a place to start). I am able to say given game design X the payout percentage will be Y. However, I don't quite yet have the "feel" for how to finesse X to subtly adjust Y. For example....say I have mathed out a game in certain configuration that will pay out 92.5%. My boss now comes and says they want a version that will pay out 92.6% or 93% or some other value.
Is there any research/book I can read or class I can take that delves into how that is accomplished? Or, is this more of a seasoned "feel" thing that will get better with more experience?
I've been tinkering with reel strip configurations but apparently I don't quite yet have the knack for zeroing in on a target.

Thank you for any assistance you can provide.

There are no classes on the topic, to my knowledge. I learned from doing.

But your inability to immediately adjust the payback on a game by "tinkering with reel strip configurations" tells me you're probably not using a spreadsheet but custom software. Use a spreadsheet, or adjust your software to do live updates. Otherwise it'll take you forever.