Also, unless they changed it (doubtful) you won't just be able to jump into the higher tier Guardian raids. In order to access a new Guardian tier you must have defeated all the Guardians in the previous tier. Fortunately you can do this without having to deal with a daily lockout, because the daily limitation for Guardian raids only affects their drops, you can enter and kill them as much as you want. Unfortunately, some of the final Guardians of each tier have a party wipe mechanic that is a pain in the ass. I usually wait until I have high enough GS to solo these with enough dps and using certain consumables and tactics (like sliding down ladders to avoid the one shot).