That way works as well, though eventually it just gets tiresome repeating the same process over and over. The way I suggested is more permanent. Inevitably though, I expect Vren will resolve all this as he goes, since it's already been said he intends to include the ability for the MC to manipulate his own characteristics (size, sensitivity, etc).
The code for the girls arousal is located just above the code for the males arousal as well, and can be altered in the same way as the males. The SB mod already makes use of inserting variable constants throughout the code to control various values in its mod. Would be easy to add a couple new variables to its SB_constant_declare.rpy to allow altering the arousal multipliers that each person can adjust to their liking. Hopefully they'll see this and include it in their next release once 0.14.1 is released.
Me picking through the script code in the first place was caused by being tired of opening the console or the cheat mod all the time, so I looked for a more permanent solution. I also looked into Trollden's cheat mod and considered adding an arousal "lock" toggle of some kind. Just lock the male at 90% at all times so you can finish whenever you like, but couldnt figure out a way to do it without altering the script.rpy file, thus making it impossible to accomplish and still be compatible with future updates without having to make the necessary changes after each release.