I would suggest that you organise a balanced rig ... how you organise this is up to you ... a ring around the lens which mounts on the tripod with the camera 'hanging in the air' or another approach is to have camera and lens on a rail ... in both cases one achieves a balanced rig instead of hanging a heavy lens on the camera mounted on the tripod. The rail should have the advantage that one can adjust the balance point if pointing the camera upwards or downwards. I made a collar when I added a heavy telephoto adaptor to my bridge camera but have yet to make a rail or have gear like you are contemplateing
I used my rig on a monopod which was made so I can comfortably stand without bending on the principle that my legs are the 'other two legs of the tripod' and to work efficiently they need to be straight and relaxed ... just my theory for your consideration ... the problem when buying gear is finding stuff made by people with similar ideas to yourself.
I haave made several monopods over the years for specific needs* utilising the feature that aluminium square tube [ or circular for that matter] slides inside each other as you go up the sizes and then all one needs to do is organise a screw to clamp each section ... if you are a DIYer that could be an option though over here aluminium is sold in five metre lengths which makes it costly unless you have uses for the 'offcuts'
I made my mono's out of offcuts from other jobs.
* Like one which fitted in my suitcase when I went to the States.