DONT use SLI. SLI is purely for making old games run slightly faster, it does not make rendering faster in any way. Turn your machine off, remove the SLI bridge and just run the cards independently. Then in your arnold settings ensure both independent gpus are selected.
Yes, you can switch between ops like this
Type in switch node has to be neutron::ObjectPackage
Please keep in mind that you are using experimental scene node graph and nodes. Capsules (nodes mesh, nodes splice, nodes modifier) are mainstay of nodes in C4D and have polished features and workflows.
Given your version my nodes solution will not work there. For your issue #2, use a sphere as a parent of field itself. You can create circular spline and use an align to spline tag and have the planet "orbiting". Also try using push apart effector with negative strength instead of plain effector, maybe that would give you better results
Here is a setup which showos how to do particle to particle collision. Although there is no real collisions available at this moment, some modifiers can be adjusted to do a very convincing job 🙂
Bubbles.c4d