Using a tray IOT support the weight of the Tx on your shoulders/neck rather than hands is a great modification. Using longer sticks gives you the ability to adjust your position both to be able to change position as well as achieve one you find most comfortable. I would consider wrapping the transmitter sticks with medical foam tape both to increase the diameter and to provide some degree of cushion requiring less flexion of the involved joints as well as less grip pressure. You would have to determine the right diameter by trial and error on the basis of what reduced pain and gave you the most comfortable "feel". They make oversized softer golf grips for arthritic players for the same reason. If you are using a "thumb" rather than "pincer" grip, might want to change as the latter transfers more motion to the wrist rather than finger joints (I am making an assumption as you did not actually specify which joints were involved but RA usually hits the fingers prior to the wrists). Also keep your hands warm during the activity, consider gloves with a good "feel" probably golf gloves would suit best. Cold/ice does have a role after activity both for RA or other inflammatory arthropathies (which is what I assume you have) and OA both to dull pain and reduce inflammation but will cause significant stiffness during activity regardless of the underlying cause. Good luck