When moving any acid around over a period of time, I would not use any plastic that could dry out, crack or in any way get brittle from acid or heat or any outside influence ! It may be a bit exotic, but, I understand that the refineries which produce these acids use an extruded CP Zirconium tubing (CP = commercial purity) These tubing supplies or other suitable should be available from somewhere for your system. It would be a disaster if anything broke or leaked causing a release of acid within the shop or on any personnel. Glass works good but too easily shattered for a portable system. Unless my memory is totally defunctified I am pretty sure Zirc is inert in use with acid. I used to machine billets and liners that were assembled and drawn out for just that purpose, or so I understood at the time. All we did was the machining, then shipped to customer for the rest of the process, so info I got was hearsay !
Don
IH v-3 early model owner