Ahoy there, just thought I'd offer my perspective on this.
Yes you can definitely run them 12-12 from seed and get a good impression of the strain. If you grow it well, get the environment right etc you'll have the same results no matter if you grow in a 25 litre tub or a 2litre bottle. I've been running clones of a few strains lately, growing and testing them in different styles - topped and untopped, 2l pots, 5l pots etc. I've not noticed any difference in performance other than the cuts in bigger pots having more branching going on.
Cloning wise I've been experimenting with that too and I've successfully rooted cuts taken up to 3 weeks in flower. After that my success rate drops off and it's a gamble. You're also more likely to lose cuts due to mould in the proto buds unless you trim them off (I learned the hard way)
The one thing you don't mention is having a separate veg space but you'll need one to do any cloning as they won't root in 12-12 and you can't keep the mums. Although I'm guessing you have that sorted, just a wee thought in case others are reading this.
I'd say your plan sounds good, you could definitely run a 12-12 from seed, take cuts once sex has shown and have them vegging whilst you finish up the seed plants, smoke the results and make some choices on what to keep.
You could also take the cuts early on before they show sex, that way you can toss males or keep them if you find a really good one and want to make crosses in future.
Only other thing I'd add is to take two cuts at least from every plant you want to clone. Again, I learned the hard way on that one.
Ultimately it's horses for courses - everyone has their own way of doing things based on their set up and growing style. WelderDan's technique is much more professional than mine but does require more time and space. I tend to run smaller pots with less veg time to run numbers, look for keepers and make seed runs.
Experiment, mess around and don't beat yourself up if you lose a cut - experience and mistakes are how we all learn. Some of us quicker than idiots like me but it's all good.
Hope this helps
Ganja gu brah