I did this and after level 10, the lowbie (without looms) was getting about 4 bars per clear.
It's not about how much XP per mob you get - its what portion of the level it's getting per clear since the XP per mob will change every level. I found this a whole lot easier than questing - doing the whole /follow thing etc on my own. Who actually recruits friends anyway?!
The number of bars of XP varied and each time I got an achivement (e.g Level 40! or Level 70!) I found dungeoning far quicker for the next level or two (e.g. 70-73). I just dungeoned the first couple of levels each time I dinged a multiple of 10 and then carried on. When I say dungeoned - I played one lowbie and botted the other as a DPS.
Total played time on the Loomless RAF Account was double what it was on my lowbie on the real account. That said, I didn't use this method all the way as I got so bored.
Happily pulled the whole room with a Protadin @ 85 - Seal of Insight and some DPS trinkets.
Use your guild banner for an extra little boost.