H200 Hayward heat exchanger repair

I was given a heater with the used pool I purchased. Previous owner indicated it worked, but leaked. I decided to see what was wrong. As it turns out there was lots of pin holes and thin metal where the stainless steel heat shield contacts the copper. Most likely corroded the copper due to copper corroding against stainless steel because of dissimilar metals and the Stainless being more of a Nobel metal and the copper being the one to corrode. The tubing used to make these axchangers are of a strange size. Doesn't seem to correlate to HVAC or plumbing copper sizing. I had to make my own size pieces by swaging 1/2" copper sweat connectors. I thought I would explain my repair as these heat exchangers are expensive.