When to change from train to custom

Just a quick question:How long should i leave firewall setting in train?I have ran most programs on my system{updates etc},and was wondering if i should now change behaviour settings to custom.If so and i install a new program/application would i just return to train mode,run the program/application so comodo knows its ok then go back to custom.So far all seems well,just 1 query,i am on cable with a router{lan} after the modem(shared with 1 other computer but no interconnection required).What is the best setting for stealth ports wizard?do i just leave on define trusted network.

Sorry i know i said just a quick one(oooh), but as your writing aspects about the “FIREWALL+” just pop into your head.

Kind regards Matty

WIN XP PRO SP2/AVIRA AV/COMODO BOCLEAN/ COMODO “V3” up + running :BNC