Alternatively, use a hammer 
other blunt/pierce weapons will also stagger the huscarls but I find the sledgehammer works best on these fuckers
Wave 8 is fine, you could add 'help your team to take out the captains first since they will charge ahead of their troops and are the most dangerous enemy''. For wave 9 and up, against troops with shields one of the easiest methods is letting one teammate lure some and then another smacks them on the back of their head. Just don't engage them up front if your level isn't that high. Wave 15: if you see a Nord Ranger standing alone somewhere blocked off from his teammates you can to get him by zigzagging and then spamming him. To battle Nord Knights you will need a high damage dealer or an anti-armour weapon such as a pick (bugged), mace or hammer, but first you will need to dehorse them or move somewhere their horses can't go (no glitching).
Somewhere in between the waves you have listed there are also Mercenary Zweihanders, which should only be engaged in singles, to stagger them you will need a high damage dealer or anti-armor weapon and you can kill them by holding each swing a second longer so that they start their attack when you are about to hit them. They carry greatswords which can already be used at level 2 Infantry and are pretty damn nasty. I'll let you know when I found out which wave btw
Hired Blades are also in some waves and aren't that tough, same tactic as other shielders except their shields can be broken easily with axes.
other blunt/pierce weapons will also stagger the huscarls but I find the sledgehammer works best on these fuckersWave 8 is fine, you could add 'help your team to take out the captains first since they will charge ahead of their troops and are the most dangerous enemy''. For wave 9 and up, against troops with shields one of the easiest methods is letting one teammate lure some and then another smacks them on the back of their head. Just don't engage them up front if your level isn't that high. Wave 15: if you see a Nord Ranger standing alone somewhere blocked off from his teammates you can to get him by zigzagging and then spamming him. To battle Nord Knights you will need a high damage dealer or an anti-armour weapon such as a pick (bugged), mace or hammer, but first you will need to dehorse them or move somewhere their horses can't go (no glitching).
Somewhere in between the waves you have listed there are also Mercenary Zweihanders, which should only be engaged in singles, to stagger them you will need a high damage dealer or anti-armor weapon and you can kill them by holding each swing a second longer so that they start their attack when you are about to hit them. They carry greatswords which can already be used at level 2 Infantry and are pretty damn nasty. I'll let you know when I found out which wave btw
Hired Blades are also in some waves and aren't that tough, same tactic as other shielders except their shields can be broken easily with axes.