I had some interesting material leftovers from a work earlier this year, and decided to build a dolly for my iOptron CEM40+Literoc tripd. What's good about this material are the fittings, and also the format with a slot for M8 or 5/16" screws and nuts.
For this build, I used two pieces of that profile and a joint:
Joined them together with the joint (needed to drill holes for 3/16" screws both on the longer piece and the joint).
Joined all main parts together. The profile is really tight on the joint, needed to use a rubber hammer to put them together:
My tripod is the iOptron Literoc that has vibration dampeners permanently installed. That made the attachment between the tripod and dolly much easier. I used a large washer that will be used to attach the tripod to the dolly, through the vibration dampener. This cannot be tight, or the dampener loses its function.
Finally, installed the tripod. The inner part cut above was turned into the handle of the lifting screws:
Tested it last Saturday, worked fine. The casters I had laying on my desk for months have 7/8" wheels, making the whole kit a bit shaky. When I can, I'll put bigger casters. Also the bare end of the lifting screws scratches the pavement, I'll put a rubber or wood end there.