Do we time events in a Solar Return in the same way we time in horary?
It is not like horary. Horary is very specific, there is no ambiguity about significators. Natal and derivative charts can be specific only when we study known past events, otherwise it can be as vague as to be meaningless when it comes to prediction.
With most SRs, we cannot be sure that aspects on SR refer to this or that event, or to any significant event at all, unless the context is EXTREMELY well known. For example: a breakup shown by the Moon conjoining Mars for someone whose marriage is in tethers. Or L1 aspecting L9 for someone who is already planning to move to another country. In that case we know she is not going to enter university or meet her life-changing guru, and that a move is likely in the works. Otherwise, if there is no solid context there is no such thing as prediction using SR, let alone timing. And really, even with a good knowledge of the context there can be doubt simply because a planet can signify more than one subject or thing.
Also, many years can go by without any event significant enough to appear on an SR. However, SRs usually show the year’s “themes”, not events, per se. For example: Natal arc Fortuna conjunct L5 in an SR, you can expect lots of artistic activity or activities related to sex, fun or children, according to the context. Or the Moon conjunct Natal Arc part of Captivity, we can expect more addiction in the life of an addict, rather than freedom from it. Or L1 conjunct L12 but L12 is also the Lord of the Geniture, we can expect both self-undoing and serious work to overcome it. Etc… Always with close relation to the native’s actual present life context.
Having said that, if there is a potential major event shown on the Solar Return, then the event will show up in one of the Lunar Returns for the period. That is one way to narrow down. It certainly works wonders in retrospect and we can learn a lot about symbology and technique. And it is entertaining. But if actual prediction is needed then horary is a much more accurate tool to be used.