Rootes1725cc

Hello, my old man is having trouble fine tuning the carb on his 1967 mk11 sceptre,it was fitted with a twin choke webber but now has a solex,he changed it because him and his dopey old mate dont know what the hell they are doing anyway.Now they cant get the solex to run right,it's got all new gasket's so should be ok, but the dopey old mate who think's he's a marvel mechanic,cant seem to set it up,what's involved,i thought just get the motor warm,and adjust the mixture screw should do it. Any help would be appreciated as watching these two old fart's argue is getting old fast !