Well, gee, I don't know - enough! LOL!!!
Sorry - someone probably has a good idea of what athletic skill it takes to "climb" the spire, but I'm not one of them
Give it a try with what you have now and see if you can manage it.
Do you have Create Portal, Teleport and Call of Home yet?? If not, get them SOON!! When you finally make it to Brimloch Roon, set yourself up a Portal on the east side of the gate so that if you feel the need to return again to Ishad N'hahahaha you can just teleport back! MUCH easier!!
Wyv