One of the issues associated with lowering your bench height to be ideal for planing is that it is quite low for other tasks. Several years ago, woodworkers began building or buying what is variously called a bench on bench, a bench raiser . . . such as this example. Sometimes it has a vise, sometimes not. I decided to build a very simple one as an experiment. In fact, I made it from a single 4x4 and some scrap pieces of 2x6 in a couple of hours. Here it is:
The 2x6 base runs lengthwise to avoid expansion issues and provide an extension to clamp the bench to the main bench if necessary. As you can see, I went overboard with dog holes.
I use this bench on bench very frequently, such as here where I am chiseling out the hinge leaves on a Roubo bookstand. My aging eyes really benefit from this and I find the height very comfortable for tasks like this (34" main bench plus 7"). I also use it behind my Moxon vise when laying out dovetails. It lives there or under the bench when not in use. This is one of the many nice things about having a long bench.
Where I live, #1 douglas fir 4x4s are readily available at low cost. The grade is higher to meet structural requirements in building codes. I buy several and put them in the corner to dry so I have them for projects like this.
You may be happy working on your bench all the time but, for me, this was an experiment that turned out very well.