Level 1 YT City / Level 4 Wilderness-----80 Archers
Level 2 YT City / Level 5 Wilderness-----160 Archers
Level 3 YT City / Level 6 Wilderness-----400 Archers
Level 4 YT City / Level 7 Wilderness-----800 Archers
Level 5 YT City / Level 8 Wilderness-----1600 Archers
Level 6 YT City / Level 9 Wilderness-----4000 Archers
Level 7 YT City / Level 10 Wilderness----5000 - 8000 Archers
Level 8 YT City-----9000 - 16000 Archers (Can be less depending on hero level)
Level 9 YT City-----30000 - 40000 Archers (Can be less depending on hero level)
Level 10 YT City---40000 - 80000 Archers (Can be less depending on hero level)
About 1K rookies per level of city should be alright. I'd use 1/4 pikes to archers (250 pikes for every 1000 archers) and 1/3 swords to archers (400 swords for every 1000 archers) to attack, not used for tankers. The archers are still the best, but when it comes to walls, the ballistae and battering rams are actually better.
Remember this is for YT CITIES! Any loyalist cities (likes those with BROQ). The royal cities will have other things like ballista, rams and trebuchets. YT cities will not have those things and thus are more easily manageable. If fighting against a loyalist, remember to to deal with Trebuchets as soon as possible because their far range will make it difficult for you to hit them as well as allow them to deal damage to you unopposed. And also remember it only applies to marauding of YT cities and NOT conquering of the YT cities