Your ‘toolbox of tricks’ evolves and grows overtime….

I run a re-calibration of my short terms systems every 6 months or so. I.e. optimize a parameter to ensure it’s in ‘the sweet spot’ / robust etc

FWIW:
My MR#1 system core rules haven’t changed, just a small tweak of 1 parameter during re-calibration since launch etc… My MR#2 system, I did end up changing the core rules (effectively a rebuild of the system).

Nothing wrong with changing the systems up, just as long as it’s for the right reasons etc.

With your 2nd second system VS your 1st system….. run a correlation test to see if they are ‘close’ or ‘different’ in terms of their car/mdd periods….. i.e. when 1 is doing good, is the other 1 in drawdown etc….. sometimes it’s not always about the best returns, but the smoothness of returns….. From a psychological point, this might offer a nice balance etc.