This is one of the reasons I am waiting on 4- 4x5 tanks with floating lids, I bought from another guy on APUG.
I do my E-6 at home, mostly with 35mm and 120 in daylight tanks. I am currently using up some out of date Kodak chemistry, but have also mixed from scratch in the past and have achieved quite good results that way.
For 4x5 the daylight tank I have for the hangers takes too long to fill and drain, and does not pour elegantly in the dark with the lid off to sped up fliud transfers.
So my plan is to set up a sink line to process my LF e-6.
I find that 'the film guy' at camera swap shows around the GTA has such a glut of 4x5 E6, at very reasonable prices.
It may need a wratten in front of the lens to correct shifts, but at $15-20 for 50 shhets, I am not going to bitch about those little issues.