Setting up dipstick
Basically just get a parts-store dipstick and shorten the tube if you need to adjust the level of the stick, you could also shorten the stick itself if needed but you have to make sure to put marks on it. The key is to have the engine at the same angle as in the car and then fill up the pan with the exact amount of oil the pan is advertised to take. This can be tested with the pan off the engine using water to check how close it comes to the baffles etc. Once the sump is filled and the engine has sat for 10 minutes or so to make sure all the oil drains down put the dipstick in and see where the oil level is. Wherever the oil level comes up to is going to be the FULL line on the stick.
I just went through this for my Magnum build, got a parts-store universal replacement and without cutting it the marks aren't too far off. I just know it needs to be filled a bit past the FULL line, I always count how many quarts I put in anyway when changing oil.