I like your answer, and that's a really cool tool, and will be very useful in setting up a production chain, so I voted it up. I agree that it is possible to underclock the screw constructor to match conveyor speed, and then just add an additional throttled screw constructor in parallel to compensate for conveyor speed, you will still run into a bottleneck at the single import slot of the iron reinforced plate assembler. Granted, this is no longer an issue once you upgrade your conveyors to the next tier, and I guess it's not a big deal.
Even though you answered my post, I still have some questions about how this was balanced during the test weekend:
1. I guess the thing that just doesn't make sense to me is that it just seems so very strange that they are using a part that in real life has proportionally far less volume and mass compared to other parts in just about any assembly you can think of, and yet when transported across a conveyor, it takes up 6 times as much space. When was the last time you ordered something that required assembling (a common thing would be furniture), and the box it came in had like 85% of the space taken up by screws and 15% by metal/wood sheets?
2. Ratios are everything when optimizing efficiency in a game like this, and your answer sheds some light on creative ways in which you can optimize efficiency by underclocking constructors which is kind-of a new concept, but as you pointed out in your comment after, setting all of this up is really time consuming and since you are reducing the speed of your machines, you are effectively reducing efficiency. This is mainly because the ratios of products using screws aren't aligned well at all with the components that they are made from.
Take rotors for instance. I used the tool you posted and incremented the quantity produced until I got whole numbers on each production machine. The absolute smallest setup to accomplish this (ignoring conveyor bottlenecks) is the following (at 90 items a minute): 20 iron ore miners, 20 smelters, 40 iron rod constructors, 22 screw constructors, and 15 rotor assemblers. Half of these numbers (at 45 items a minute) are possible to keep all sub-parts at 100% production, but the final rotor assembler would be operating at half speed. Anything less and one or more of the machines in the production chain will under or over produce items. Even with overclocking/underclocking, figuring out the exact clock settings you would need on each machine is not simple without a tool like the one you linked. This could all be balanced by sticking to a specific ratio when setting production values of machines. Having strange ratios like producing 6 screws each time but needing 22 screws for every 3 rods, it's just not balanced well.