Loco Louie's was indeed the best color rep insert ever made. These are no longer available except as M2M and would be quite rare and expensive as few people would part with them. Louie quit the business without fulfilling many orders, ripping people off as he disappeared.
Currently, the VRF Max is the best color rep insert available. It's green is slightly lighter and more gen-like than Noob, ARF, BP, DJF. It's very hard to pick that color difference up on camera but it's there. The other thing about the VRF is that the markers don't look dull in low light or on an angle. It's the only one I've seen that has that characteristic.
VRF inserts are not available separately that I know of. I have tried several times. I still have a $60 credit from one TD from a year ago after he was unable to source one for me. Ceramic inserts are swappable among bezels, generally speaking. You don't need to buy or replace the whole bezel. In fact, trying to do so can run you into more issues with bezel gasket damage, or crystal retaining ring compatibility.
VRF insert is quite pretty, pleasing to look it. Other rep inserts made me think, "wow that is (... dark, ugly, army green, etc.)"