There are several coil testers available for testing and adjusting 1913-1927 Ford and KW coils. There are other coils used for earlier 1909-1913 model years that are not easily tested or adjusted using the available testers. The lack of a cushion spring on these coils also make them much more difficult to adjust to achieve satisfactory performance.
I have had good success adjusting Kingston coils using the dwell time to fire method of coil point adjustment and was considering making a dedicated tester just for Kingston coils. Perhaps it would be possible to make a universal coil tester capable of testing and adjusting Kingston, Heinze and Ford/KW coils on the same tester using the dwell time to fire method. Do you think such a coil tester be of interest to folks or not. Any other types of popular coils? Thanks in advance for providing your comments and suggestions.