get yourself a grand soulgem and kap a golden saint, go to your enchantment screen and load up your new 80k gem and the item you want to enchant,youll notice you can now make constant effect items, now here comes the cool bit, replace the gem with a crappy one and youll see you can still make constant effect items without the need to use use up your nice new gem
tryed this with a winged twilight (60k) didnt work.
sorry about the bad grammer
hope it made sence.