One source says Abamectic is a General Use Pesticide and is rated as a toxicity class IV, practically non toxic. Then you read further " Abamectin is highly toxic to insects and may be highly toxic to mammals as well" I do not find much about Fenbutatin that makes me think well of that either.
Understanding something about the life of Spider Mites could be of great assistance in controlling them, and the link attached leads to a very good article about them.

Here is a link that might be useful: Controlling Spider Mites

one might suggest you look into mitecides ...

but i dont understand how there is anything living in your garden ... bugwise i mean ...

i would really hesitate as to more spraying.. it just shouldnt be needed ..

damages leaves will not get better.. so be very careful in thinking there is ongoing damage .. until you see NEW GROWTH affected ... otherwise i would presume you solved the problem ...

you have used more chemicals and oils .. than i have in the last decade ...

as a group.. we should be very careful in recommending more solutions ...

ken

Please know that miticides are a very radical course to take unless there are no other options. If you even bring the pressure down by controlling the population of spider mites, you might find that predators and even the spring weather will take care of the rest of the 'clean up'. Your best bet is to bring it all back into balance and avoid using an arsenal of chemicals for mite control.....they will destroy the beneficials you need that will ultimately keep them under control.