Selling miners is not like selling tomatoes. If you are dealing with tomatoes then you have to sell fast because they don't hold for long. But if you sell miners you have the time to wait and let the people who are buying your product the opportunity to get their investment back otherwise they don't buy your miners in the future!
Without profit no more buying so simple is it. There are many people out there putting a lot of money in mining projects. Customers who purchased miners and developers too. Why do you think iBeLink and PinIdea made the decision to sell batches of 50 miners? Right because if they sell 5000 miners each batch then their customers don't make profit because the difficulty is going to fast up. In this case they made only ones profit in selling 1 batch and no other batch in the future. Because nobody want to get burnt again.
So better produce and sell miners linear to the price of dash and the difficulty.
For example:
1. Begin with selling small batch 150MH.
2. Sell next batch 150MH cheaper than the first batch.
3. If DASH price and difficulty went up then let next batch be for example 450MH or as much needed to be profitable and calculate the price for the miner so that your customers have their ROI fast and make profit fast so they have enough buying power to buy your next batch.
3. Sell next batch with the same hashing power cheaper than last.
4. Look at DASH price and difficulty and decide how much hashing power is needed to be profitable and make the next batch for example 600 or 750 MH.
5. And so on ...
You know what I mean u must have a business plan not only produce and sell as much and fast as you can! Your business, DASH and the network have to grow. And believe me your business can only grow if you don't have unsatisfied customers. What are you going to do if nobody is buying any more of your miners sell it cheaper and cheaper till really nobody wants your product? Or is it better to have always a wanted product so you can keep producing and selling?