/fa/ - Fashion

Just got a pair of medium grey trousers & a pair of charcoal grey flannel trousers. The flannel ones are much darker than I had anticipated which is fine, but if leaves me wondering if I should also get a pair of medium grey flannel trousers or if the grey ones I already have will fill the role of a flannel trouser just as well? I will be wearing both in business casual settings and outings, but I feel like flannel trousers go better with fair isle sweaters and herringbone / checked tweed sport coats whereas the other wool trousers would go better with traditional solid color sport coats and blazers. Is two pairs of flannel trousers in similar colors necessary for kino pair-ability?