+/- 20% is spec tolerance... or how far away from the rated values the actual component might be or sustain. From what I've seen, 20% is about as generous as caps get... I've seen 10% and 5% (as noted on your schematic) and I imagine tighter tolerances are available for critical applications also.

I'm not an electrical engineer, but my understanding of tolerance specs falls into two scenarios:

- the circuit is susceptible to creating its own fluctuating load, so the rated component is spec'd to allow the circuit to continue functioning, instead of failing or causing damage, within that range

- related to the above, the component is spec'd as a sort of failsafe: if values drift out of spec, the circuit fails (hopefully without damaging other stuff).

That said, I kind of approach it like fusing a circuit - a too-small (close tolerance) fuse might blow sooner, but prevents damage to other stuff. Too big a fuse and things get melty. So I wouldn't use a wide-tolerance part where a close-tolerance is specified, because lacking full understanding, the potential for collateral damage downstream is too great. But you *could* use a close-tolerance in place of a high-tolerance, maybe, with the understanding it may fail more quickly.

Since a capacitor is like a battery, I consider the tolerance rating as an indicator of how "low the battery could be and still allow the circuit to work". (I acknowledge there are a lot more complexities in circuit design than that but again, I'm not an EE).

It also seems to me that closer-tolerance parts are generally higher quality and more expensive. So when dealing with an "unknown" I assume it's a wider tolerance.

TL;DR, if it were me I'd "assume" your on hand parts are the 20% spec. And/or maybe a smaller tolerance spec could work there. The current and voltage are most important and yours match so again, if it were me, I would try it... but proceed with caution.

Hopefully Ed from @gpe will see and chime in here to correct me.