In my opinion "Factor Momentum" is a valid strategy. Its not easy to develop on here but I have done it. Took me many tears to fully automate it (mostly waiting for P123 functionality to catch up) and uses hundreds of custom formula and ranking systems.
I've been away for a year so haven't been active, all I can says is factor momentum is possible to achieve on P123. There is a thread from a few years ago in which I explain how it works. Can't find it at the moment...
Factor Momentum is different from Factor Weighting, but it does discover Factor Rotation. Factor Weighting comes into play once Factor Momentum is discovered, then the resulting factors are weighted accordingly.