It would be useful to use request groups. In other words, if I have set up request groups for the planets, I create a fixed platform in orbit for each planet, which becomes the supplier for the platforms that move between the planets that are requesting. Now, if the planets' requests vary, I will have to be there every time to reconfigure the requester, provider, and threshold. Does that make sense?

Can't you do this with circuits ?

I thought it wouldn't work with circuits, so I wrote what you read, then I realized that I can't get it to work even with constant combinators, so I wrote to you on Discord with the images.

Then this is out of scope for this mod. Checkout AAI Signals from Earendel, it allows to transmit signals remotely and could help you achieve your goal.

I use a "space supplier platform" in my game, I call it the Hub, over nauvis.

To spread for example Gleba Items I have the following setup:
Create a named group, like "Gleba Export".

hook a constant combinator to the provider antenna on the ship exporting the gleba items to the hub. Also put the same group in the Platform main building to request items from Gleba.

On the Hub have a constant combinator with that group hooked up to the requester, hook the same signal to the provider, but Math it to ^ 0, to change the provide threshold to 1 on each item.

All ships that need to transport gleba stuff to their planets have a constant combinator with "Gleba Export" hooked up to the Requester Antenna.

Disable dropping items on the gleba ship schedule. This forces the Hub to drop items to nauvis instead of the gleba ship, this keeps the items available in orbit.
Any changes to the gleba Export group in any constant combinator will then change the items in all ships. Changing a group on a ship to "2x" can change the item amount on each ship individually without influencing other ships (for example the hub requests 5x). Special items like the gleba flux for example go onto a separate group to prevent spreading flux to ships that dont need it.

If you need more dynamic changing amounts, as Puck suggested you best use AAI Signals or similar.