I have the 4110 micro Spey and really enjoy it on the Bow. I mainly have been using it to swing small streamers and wet flies. Patiently wainpting for the stoneflies to try skating some flies on the surface.
I found the 4wt won't do it all, it struggles with the larger streamers and heavier sink tips. The 11 1/2' 6/7 biimx that you have is better suited for that.
The 5wt is a little more rounded then either forementioned rod, I have played around with one a couple of times but haven't pulled the trigger on one .......... Yet