Thick CA takes longer to set, can fill small gaps and is used for most basic construction except very high stress areas like Firewall, landing gear blocks, joining wing halfs and servo tray mounting where epoxy should be used.
Thin CA sets imediately and can wick into the surfaces, good for tacking pieces in place where critical alignment is neccesary, CA hinges ect...
CA accelerator (sp?) speeds up cure time of all CA glues and is good to harden thick CA fillets (thick CA on top of surfaces takes a long time to cure)
CA debonder loosens CA glues for fixing goofs or cleaning spills.
That said some people, myself included, often use white or wood elmers type glue. Some never use CA at all. I mix up my building technics.