Trying a few new things. I got the DMM/TreeMagineers hitch climber pulley (HCP) and an eye2eye tail of 10mm Ocean as a gift. I checked out some of the illustrations and video guides on Sherrill Tree. What I found was, my old setup with 2 attachment points (AP's) at the center ring still works best for me. Yeah, the HCP has a great set of holes that make me wanna stick a carabiner thru 'em, but there's some inherent disadvantages (IMO) when I do.
What it does do really well, and for me this is alone warrants the $50 some-odd dollar expense, is position my home-made prusik and dog snap a little farther away from my VT friction hitch, making it less likely to interfere with the VT grabbing.
First thing I noticed as I tried this new config slow and low was, you really DO NEED a spliced eye at the end of your climbing line if you want to make a SAP as in Fig. 1. That's what they show in the drawing and they don't do it that way just for the ha-ha's.(I wanted to change nothing else except the pulley and the attachment configuration, so my old HRC tail is in this pic.) Only a few moments after I started to ascend the buntline hitch to the carabiner (arrow) began to release the VT on every cycle, forcing me to come back down. I don't own a climbing line with a spliced end and I haven't learned to splice yet. So that was that. But then I started thinking...
With a single attachment point (SAP) at the harness, if I'm coming up on a limb that is between my DdRT lines, or if I'm close to my tie in point (TIP), normally 1st thing I do is unsnap my homemade hitch climber (dog snap w/accessory cord) so I can spread the lines wider and maneuver better when deploying my positioning lanyard or pulling up close to my TIP. That dog snap with the 3mm Maxim is the extra piece I use for a hitch climber without a SAP and a DMM HCP. Again, credit to Sherrill for showing me that trick 6 or 7 years ago. Instead of the DMM HCP you can use an ISC Fixe pulley. The fixed plates allow a space for the dog snap to the carabiner.
So the HCP is great and Ocean eye2eye is great. I normally use 8mm tails but Ocean grips very well. A swivel plate pulley is easier to drop than the Fixe, but it really keeps the 3mm prusik away from my friction hitch. I also tried my HCP with a 2nd climbing line in a suspended Y configuration. Attaching your 2nd line to the HCP instead of your saddle ring provides for a whole lot more throw when you are cycling on the auxiliary line. Progress is faster and easier.