Best way for a GROUP to boost a SOLO character?

Say I want to powerlevel a single character. I've got four more accounts to boost with.

1. If I have the solo character tag a target, then have the target killed by the 4-man group that COULDN'T get XP from the target, will the solo character get all, some, or none of the XP?
2. If I have the solo character tag a target, then DPS to below 50%, then have the target killed by the 4-man group that COULDN'T get XP from the target, will the solo character get all, some, or none of the XP?
3. If I have the solo character tag a target, then have the target killed by the 4-man group that COULD get XP from the target, will the solo character get all, some, or none of the XP?
4. If I have the solo character tag a target, then DPS to below 50%, then have the target killed by the 4-man group that COULD get XP from the target, will the solo character get all, some, or none of the XP?

Just throwing out hypotheticals. The goal is to get a single character the most XP from using 5 accounts.

1. They would get some, but with 4x 70s doing a bulk of the DPS you will get *very little* XP.
2. You will get a little more XP, but still little. You would roughly get 50% of the XP. It appears to scale linearly with how much damage you do to the mob.
3. If the mob is green to the 70s, then your solo toon will get full XP. Tag and kill will grant you full XP.
4. You will get the same XP as #3.

1 & 2 is based off my attempts to do the same thing. 3 & 4 I have confirmed on a few occasions (started getting full XP a bit into outlands). There is a page on the wiki that explains boosting with pets with full XP, but it only works when you have more than two toons you are boosting.

Best bet is to use your 70s to nuke quest mobs and just rip through your quests. If you are fortunate enough to be levelling a paladin, spec it prot and make a very large pull and heal with a lvl 70 toon. When your prot pally has done a large portion of damage then nuke the rest with your 70s. I levelled my prot paladin this way and visited all the typical AOE locations when mobs were all orange. As you may have guessed, instance runs are not worth it if you bring in 4 70s. Just do them for gear runs (if you need it). Level solo as much as you can tolerate with just a healer on tow.

Awesome, thanks for the info!

well the fastest way would be to make a temp RAF account, and quest with 2 of em, and occasionally boost with 3 70s for instances. You're looking at roughly $25-35for a battlechest, if you want a zhevra thats another $30, and if you want to xfer the other toon off of the RAF account, thats $25 more.

But if you are just gonna keep it regular, I'd just pick up all quests, and have the 70s kill the mobs for you and just turn the quests in.

Well, you could take a raid of 19 L68's and do mob tagging for L50 on up in Zul'Gurub... :)

I can confirm that once you reach that stage, 3 and 4 are great and very speedy.

I used between 1 and 4 characters to boost my 5th shammy to 70 and it worked pretty well.

1) The usual boosting and with a few key quests to 40.
2) Boosting with only 1 shammy (out of group with lowbie tagging 1st still gives slightly more XP than grouped) up until around L55. This is the point around which you can no longer 1 shot stuff.
3) Progressively add one more shammy to the boost group as you level so that you can still one shot stuff. For me this meant 2 boosting (again out of group from 55-62, then 3 for 63).
4) Post 63 (or it might even be at L63) your points 3 and 4 kick in and you can let your full force rip on everything :D

I did my last level superfast by just grinding on the elite demons in Nagrand with the 4 shammies as backup.

Enjoy