Yes, the center post is where the washer is currently installed.
I did find some replacement fiber washers at Home Depot and am getting ready to get into it again.
Also, I took apart a dead Gamecube and found what appears to be the perfect spindle. The hole for the motor shaft extends out from the bottom of the spindle a little so it will press-fit fully onto the shaft. The other spindles I've tried were just barely mounted on the end of the motor shaft and seemed quite fragile. If the fiber washers don't work out I will try this.
While its open I thought I should apply some lube. I really don't want to use automotive grease (in any case, I don't have any). So I also picked up some "Super Lube" silicon grease (Quote from product description: Super Lube Silicone Lubricating Grease with Syncolon® (PTFE) has a wider operating range than petroleum based lubricants; Excellent water protection and moisture barrier. Use on Plastic gears, plastic threads, as a damping medium for Dash Pots, lubricate O-Rings, electrical motor bearings and rubber components. Silicone Lubricating Grease withstands temperatures from -40°F to 500°F.) It looks pretty good for this application. Anyone here ever use a similar grease on TGCD?