Hi Geoff,
There is no perfect toolkit that can fit in a carrying toolbox. We usualy carry a pair of screwdrivers, - and +, tweesers, and AVO meter. After visiting the job, if it requires any other tools, and usualy it doesnt, we walk back to the workshop and get it or have someone bring it to you. I insist on the staff to give me as presice info on the problrm as thay can so I can determine which tools to bring along. If it is a lab problem I have a box with tubings and electrodes, tweesers and cutters ready for the job. cheers Milan