Multiplier - how much is enough?

I'll keep going increasing my multiplier until something else comes along that I'd rather be doing. Other than that, I set myself a few goals but don't have a specific final bonus % figure in mind. Until 6ish months ago, I was playing THAT OTHER GAME more avidly than this one, however it became increasingly frustrating whilst at the same time I was learning about the possibilities of bonus strategy and donut farming in this game, which ultimately switched around my priorities between the two games. I expect another interest will likewise come along to distract me from TSTO at some point. I think it probably won't be the Futurama game, although I do intend to give that one a try.

Also, I'm pretty much expecting EA to kill the fun before too long anyway, by nerfing the techniques that we like to use. So that's now likely to turn me off this game in a pretty big way when it happens and is also a reason that I feel the need to put effort into "making hay whilst the sun shines" in the meantime. Thinking about this eventuality, I've been considering trying to focus more on building a stockpile of donuts alongside of multiplier progress. A week ago, I decided to keep a float of 400 donuts for buying event items. I might now extend this idea into the longer term by increasing my float amount each week, perhaps by 50 or 100 donuts. So doing this could provide a bit of a softer landing when donut farming ends, whilst still continuing to build multiplier with most of my donut income until that time.