10Mhz channel and CCQ versus conn rate

If I connect clients at present with 20Mhz channels and 100% CCQ only reachable with connection rate of 18Mbps. What would be the result if I would narrow channel to 10Mhz but set connection rate to 36M?

Since connection rates with 10Mhz channel is halved, I still should have a real connection rate of 18Mbps.
But can I expect CCQ to be the same?

I have AP’s both reaching strong signal level clients (any conn. rate works) and some marginal signal level clients.
Since clients are subscribing to a 4Mb/1Mb service I am believing 18Mbps connection rate is minimal needed to deliver such speeds.