Review on Enhance your water flow with Delta Faucet RP32104 Monitor 17 Series Cartridge Assembly by Brandon Kraemer

I have two 1990 Delta Monitor valves with separate volume and temperature controls. One has a bath and shower and the other shower only. Both stopped holding the temperature when the volume was reduced. I was hoping to upgrade the entire fairing set but unfortunately my decorative cap/rosette is quite old and has screws on the bottom at 5/7 o'clock instead of 1/7 which Delta support says I need to open the walls to replace valve body/piping. Definitely considering buying a Delta Grip Pad Kit and a Danco Universal Grip Pad Kit as a hack to upgrade, but haven't tried to see if they match yet. This cartridge was the right part for Delta. supports my clear "senior bath/shower at 1500 or 1700". Since I had to use the adapters included in the bag, the instructions make it appear I have a 1500. I had no trouble swapping out the tub/shower cartridge, although I did notice a small gap between the handle body and the valve body ( 1- e photo), which did not bother me. Then replaced the shower only cartridge and noticed the old cartridge was split in two making it apparently reversible. Now this new cartridge, which can only be installed one way, has been hot/cold swapped. I can't find a reversible replacement cartridge, although I think I could try cutting a new groove in the valve body to flip it. Also, the gap on this one is between the body of the shower handle and the temperature control knob (2nd photo), which is much more obvious and definitely looks wrong. I see other reviews have this gap too. I'm not sure what differentiates my two valves to cause this. I suppose I could sand down the plastic rod to reduce the gap. Luckily I plan to completely renovate the bathroom where the cartridge is upside down and has an ugly slit in the next few years so I can then replace the entire valve body. UPDATE: I was able to cut a notch in the valve body with the Demel valve on the opposite side to allow for a reverse install. That solid hot/cold switching with no plumbing. Not sure how common my use of inverted cartridges is, but hopefully this comment helps someone.