That looks like a pretty cool hx. I am a little concerned about the solder joints. You say that the pipes are soldered into holes drilled into the 1'' . I would be worried because all the stress is on the solder. Most solder joints into pipes like that are a t-tap style solder joint where the pipe is actually pulled outward to make a sleeve fit like any type of sweat fitting. Same thing for solvent weld fittings. More surface area for the solder or solvent to cover and take hold the stronger the joint and then the stresses are exerted on the two materials slid together not on the solder alone. Now if that was a weld joint that would be OK.