just "dig" and ask dnsmasq if your cache is really the limiting factor:
dig +short chaos txt cachesize.bind insertions.bind evictions.bind misses.bind hits.bind auth.bind servers.bind
from my perspective, ageing cache and the ttl (or lets say ttd) is the reason for low cache hit rate. i thought about overwriting ttls given by upstream server, but this is violating the dns architecture in its global meaning. this one reason i stopped tweaking these values.