Consider yourself as a "Micro-breeder". a breeder that specializes in quality, personal service, and an asset to your customers.
With that said, do not use "baby" mating nucs. There is NO way you can evaluate a queen on a 5x5 piece of comb, with a cup of bees. Leave that to the big industry "producers". You want to be a "breeder". And there is a huge difference.
Beekeepers WILL pay for service, quality, and your personal attention to doing things the right way. That means raising your queens on untainted comb, selling verified layers, and concentrating on customer service (My weakness
) You will build a following and with happy repeat customers, you do not even to have the overhead of advertising, etc.
If you want to raise 30-40 queens at a time, you will need enough nucs, one for every queen raised.