what BJ wanted to say is there is not big chance you actually get into clan which owns those clan halls, what stiba said is bullsh1t, just because he has CH in giran and isnt competitive but just casual pleb, doesnt mean he recruits random people who are low levels, he just uses it for his personal use of his old clan members or current CP
but like others said, CH buffs are irrelevant anyway, only thing why people need CH is for getting 50% back after death or buying bsoes/crystals
if you really want to make casual CP, you gotta do it yourself pretty much, write proper topic on forum what kind of people you are looking for, create discord server for this casual CP so you could have voip + some text communication (could be helpful to write there for example if you are planning to play that day and you know +- when to ask if someone is going to be, or you know, if someone says he will play at some hour, you could maybe plan your day slightly different so you could play with them etc.), try to invite people and see for yourself who works ok with that cp and who not, nothing is easier to test people out (worst case scenario you just kick them from discord and thats it), eventually you start to know some of those people, maybe start to share some accounts and you will farm some kind "core of cp", from then on it should be easy to continue
last suggestion: dont actually look on what class the guy who is interested in your cp plays, any class can work out in this kind of cp, you just cannot have too high expectations (as for example you are never going to pve/pvp as good as normal CPs)