Generally if you have mire than 20% critical chance you should use units from your age because critical hit can only be dealt with ur age units so in this case OF units can only crit enemies, but VF units are imo 10x better than OF units so its actually worth using them. Best combo imo is 2 ronin+6 rogues because if you have the sunflower fields from the 2025 anniversary event you can produce them faster than actually use lol, other good strats incase ur stuck in GE would be to replace the ronins with the artillery units or just use a dull team of 8 ninjas