Precision Seeder for Mint-family Herbs II?

Thanks Richard for your informative answer to my question on sowing herb seeds. You have obviously saved me a lot of time and expense.
I purchased seeds from Richters in 1999 and successfully cultivated them in an experimental plot; the 1999 catalogue stated volume of seeds required if directly sown per acre, so I was led to believe it could be done?

It is always possible to grow herbs by direct sowing, but it becomes a question of practicality. Generally the problem is weed control. Direct sown material usually can't compete against weeds. That means you have to cultivate or use some other means of weed control, and that means planting in rows with plants in the rows even spaced so that mechanical and hand weeding can be done efficiently.
Direct sowing becomes more realistic if you are using chemical means of control, but that is rarely an option in today's market that pays a premium for organic material. Richard Alan Miller deals almost exclusively in organic material so that is why he always advocates for transplants as opposed to direct sowing.
Having said that nothing is written in stone and it is possible that you may have found a way to grow these herbs efficiently using direct sowing methods. For example, if your fields are very clean and relatively free of weed seeds, then you might be able to get a decent crop with direct sown material without a heavy labour cost of hand weeding.

I will purchase your book "Getting Started" and take it from there.