Supa and I are actually creating a comparative dataset for AT as we speak, should be done by end of week to show case difference in HP per room, exp rates, clear times, respawn times and skeleton stats. This should give you an idea of which area is most beneficial and which area requires a touch up.
To feed curiosity Ltgen gets around 360k/h with a cumulative room hp of 17k. Gen nets about 233k/h with a cumulative hp of about 22.5k hp. Fdm hits 430k/h with a cumulative hp of 23k. The variance is huge in scrolls which requires more than small samples. Thats why fdm seems more on the high side and gen slightly on the lower end. Additionally, this is as a AH stun/b2/stun/b2/b2 which maximizes kill speed. Very few races can replicate speed so this is optimal exp rates. You will most likely have much lower on warrior/at/sorc at higher ranks (gen/fdm).
Hope this will help