How to use arrays inside of callbacks

..... perhaps you wanted to use this variable instead as the array index:

byte SignNum = 0;

Poor choice of variable names .... "SignNum" and "SigNum".

You are absolutely right! I completely missed the 'n' in all the times I looked at the code. Yes. Poor name choice. It is now SigIndex.

So it is completely acceptable to use struct arrays within the that class. One just has to not toss in extra characters.

Thanks very much. Problem solved.