barranak,
but I still don't understand the best way forward.
Neither do we - until the time arrives!
Consider all the choices and pick a simple one at the time.
Weather, colony strength, forage, haste (or otherwise) and other factors may make the decision very very obvious, or perhaps there may be two or three equal(ish) options at the time.
In your location I would hazard a guess (all hives being equal and an average good year) that your colonies may be getting near to swarming at the close of the OSR foraging and that might be a good time to A/S, or split.
You might wish to demaree one of your colonies, to induce supercedure cells from the queen you may prefer to increase from, and use her queen cells for any splits with other colonies. Whatever you do, keep it simple and within your capabilities (you can't try all methods in your first season, or at least it would be ill advised to try).
Just don't know until the time. Decide which methods you can handle and/or prefer and go that way if the opportunity presents itself - but keep in mind the other alternatives (if they come up as appropriate) or instead of, by virtue of the preferred method not suiting the conditions.
Think back to last year? So many got caught with the unseasonally warm weather in April and then were waiting weeks because the weather was too cold for mating flights for most of May. Think of what may be ahead, instead of blindly rushing in at the very first 'apparent' opportunity. Mostly my warnings went unheeded or ignored. I sorted for my new queens at the end of May and beginning of June last year.
Some like Hivemaker (hugely experienced, and has a different climate down there) started early with his queen rearing and was lucky (weather-wise, compared to a lot of us) and was successful from the first attempt. He would not have been phased if his first grafts had failed and would simply have persevered with repeats.
As a beginner, don't 'put all your eggs in one basket'. You might come up 'smelling of roses' or you might have to start from scratch again - not so easy for the inexperienced to have to 'change lanes' at short notice.
Just don't worry about it. It will be simple when the time comes - but be prepared.
Regards, RAB