I know what most bass players will say about a set of flat wounds. The sound is too smooth or dull for their playing style. In general that is a true statement. Many other players also shy away from the heavier gauged strings also. They prove to also thicken and darken the sound. At $35 dollars a pop there are many reasons not to ever try these strings. I would say you are doing yourself a disservice as these are the best flat wounds I have ever come across.
The Steve Harris custom set has been used by Steve Harris for many years. I found that before ever using the string that Steve Harris had a bass sound that fit right in the pocket. They provide a thick and underlying sound but are still full of definition and always discernable in the mix. I have been using this set of strings now for almost four years. Before trying this set out I went through many different brands both round wound and flat round. There were many that I liked but none that I loved. Unlike guitar strings testing many varieties of strings can become a financial burden fast and as bass players we try to scrape every ounce of life out of a set before moving on to the next.
These are a heavier gauge string so be ready to strengthen those muscles a bit when you use them. Being a flat wound type they are very easy on the finger tips and produce very little noise when sliding up or down the neck. I find that the sound is very easy to tailor with these strings. While not as bright as round wounds they do retain a great deal of high end reproduction somehow. They do not have a thick or muddy sound or a jazz type sound that can not be broken away from. What they do offer me is the ability to utilize them in a dark setting or a bright one. They can be mellow and smooth or with some tonal adjustments on the bass provide ample high end spank to pop and slap with. I am sure that Rotosound has done something in the process of making these awesome strings to infuse them with so much life as they are heads and shoulders above any other flat wound I have tried.