So it's "buyer beware", as no breeder will freely share what they know with a typical buyer. Let's say that someone were to place a pre birth deposit and guaranteed first pick of the litter of their choice. There's no stopping a breeder from culling the best animal before showing the litter to the prospective buyer. Or, if the breeder is more trustworthy, he/she wouldn't give sound advice on which animal to pick as being the biggest from a non-culled litter.
Same old story..............it's who you know................
Unfortunately, a typical buyer like me would have to depend more on luck than on actual knowledge, since the tricks surely take a long time to learn.
I don't at all think that all breeders are as dishonest as you portray them. Maybe the very large-scale breeders that run "elite" lines might do that, I don't know.
But if a breeder has told you that you have first choice then I would think you do. I NEVER give first pick to anyone but me, personally there's no reason for me to produce a litter unless I can select the best kitten IF I want to. I don't keep a kitten from every litter but I always reserve my right to as breeder. That doesn't mean I then sell my choice but then I don't keep formal lists either. I prefer to match kittens to homes, the right personalities etc.
The issue to me is really that most breeders would prefer to have a litter sold earlier than you might be able to determine which kitten is going to be a large one. Generally you need to wait until maybe 8 weeks of age...so then you would be asking a breeder to hold off selling ANY kitten from a litter until then and it seems most breeders want their homes decided sooner. Some of us (me included) prefer to wait until that age to really decide whether a kitten is breeder or show quality so that would work for you also, but I don't breed F1s.