A timing technique in solar returns (SR) is to check for conjunctions of transiting outer planet against SR angles. Usually, that is done during the period of the SR. I have found that you can check for the conjunctions up to 2.5 months before the period of the SR. I don't think there's a fixed rule on how far back to look. But 2.5 months certainly worked for me and my clients.
In a particular case, using the above "pre-SR start date" technique, I was able to identify the exact date of a client starting her new job, before she confirmed anything of the nature! She was the kind that kept quiet during the reading to "test" me out.
Go, have a try yourself.