Anyone with experience building tri y headers

Im looking for info on try y also. scarce , im finding it to be .Going to call a place called "Headders by Ed" here in my near future. the commercial produced parts you posted photos of I dont care for . the merge sections are too short . I believe a longer more gradual taper would be better for flow or scavenging efficency.
If I go to headders they gotta be right. Tube diameter and length sized for application .I fully expect to be building myself .
Im alright with that but I need to find council on proper design .
Good luck on it , youve got a start .
K in West Centrtal Indiana .