TL;DR
Make spidertrons inventory have option to act as different types of logistic chest, so players personal roboport can use inventory and give moveable storage in big bases.What ?
Have a dropdown menu in spidertrons logistic section where you can chose to use its inventory as it is now (requester chest) or as a buffer chest or storage chest. Storage chest mode should probably be a buffer chest that allow storage. Spidertrons own personal roboports should ignore the settings so they not get stuck with junk because spidertron is set to buffer chest or requester chest mode. All other logistic networks sees the spidertrons inventory as chosen chest type. The other logistic network chest types is not necessary because they are covered in the three types chosen.Why ?
Buffer chest mode is for when you not want fill spidertrons inventory with junk but want construction robots to fetch materials. Storage chest mode is when you need extra storage for local construction robots and want them to fetch materials. The original mode (requester chest) is for when you are in you primary base and refilling the spidertron and do not want materials to disappear from the spidertron or it filled up with junk.Players that ride spidertrons have two equipment grids to use. If player have personal roboports only in player equipment grid then the construction robots do not access spidertrons inventory. If spidertrons inventory hade an option to act as storage or buffer chest, then player would not have to manually manage the two inventories. As it is now you have to manually move the missing material from spidertrons inventory to player when doing big building project. Or you can constantly manually change the spidertrons equipment between shields and personal robot port and wait for them to recharge.
When you send spidertron to remote bases to restock materials (before you have set up a railroad) there exist now easy way to move the material from spidertron to base. If spidertron is a buffer chest and the base have a logistic network setup with a requester chest then it would automatically offload the spidertron on needed materials.
If you have a big base with a big logistic network and should do a big building project in the outskirt of base, like building a solar power plan. Then the construction robot of the base could help building the solar power plant but they have to fly over the whole base with materials and clog up the roboports on the way. If the spidertron can act as a storage chest it would be able to transport and then provide the needed materials at the building site and also give a place to put removed trees and stones.