would you be so kind and specify your maintenance intention of your published opam packages? This would allow us to push some of these into the opam-repository archive, saving bandwidth and computation time for every opam user. I suspect that "(latest)" would be a good match for your packages (or "(none)" if you don't maintain these anymore). See https://discuss.ocaml.org/t/opam-repository-archive-clarification-of-the-opam-fields for further information.
Thanks a lot. In case you have any questions, don't hesitate to ask.