Congrats on your continued journey of learning machining. Making one of these out of plastic especially delrin is going to get you seriously injured! Delrin can shatter like glass, if you try this have a lot of protection on your, well, everything! Your copy looks really close as far as wall thickness to the others. Plastic can be used in many application where metal is use, such as wear surfaces, but plastic is not a good substitute for high pressure areas and brittle plastic at that. Think outside the box, don't put yourself in one.