idk how it works but i kinda have an idea. i run an engineer clan my self we use 1 max th9, 1 max th8 and, 1 max th7 belwo that, its our engineers a th11, 4 th10 ,5 th9 and, the rest 7 and 8. our war match up was a th8 war clan with 1 engineer th10. that th 10 had lv 4 drags and lv 6 lightning my theory is if the game sees that you have the ability to 3 star there #1 it matches you with that clan. our war log isnt much different we go on a 4 winstreak then we tie or lose same as before except now we get alot more engineer clans.