Medium Sunbeams (45-105) have been one of my favourite rounds for a while now. When I experimented with Medium Pure Blues, I found they felt a bit tighter compared to the Sunbeams I was using previously on the same bass. It was not a _drastic_ difference, but I noticed the difference in flexibility. I then tried the Light Pure Blues set (40-100) and liked them much better. I've been meaning to try the Victor Wooten Pure Blues set (40-55-75-95) one of these days as well...
I think Sunbeams and Hi Beams are pretty similar in terms of flexibility, so if your experience is similar to mine, then you may find Pure Blues in the same gauges feel just a bit stiffer.