I really don't know much about this other than what's written on that issue thread. pnndra is the lead of Arduino's hardware development so they definitely know their stuff.
I'd say there's no such thing as too much capacitance in this usage. Of course, that's not a very satisfying answer for you, but I'd say just throw the biggest capacitor you have on there and see what happens. If that doesn't work, put a few in parallel to multiply the capacitance until you get something that works. After that, you could buy a single capacitor that meets the needs without being so messy as the bunch of caps wired together.