I had 2 early on but soon went to one on the right side. Full length with best pulleys I could find at West Marine. Mariner Sails also has great pulleys. The main use of my trolley is for my stakeout pole, but I do occasionally use an anchor. My trolley is full length so I can swing my yak 180 degrees.
I use this cam grip for my anchor line so I can do a quick release if needed.
I use this zigzag to lock my trolley line in place.
I use an old laundry detergent bottle to store my anchor line and also for a float on the end of the anchor line.