HERMS coil size and sourcing SS 304

Hi,
Im in the final process of setting up my 10gal brewery and could do with some advice for HERMS. I have a 30l 3kw Burco boiler for HLT (a little small but I find I can top it up and maintain temp while adding strike water to mash tun), 67l Igloo cool box mash tun with bazooka style filter (SS flexible tap connector braid) for batch sparging and a 70l stockpot for boil kettle.
With sight glass, thermometer, all valves and fittings I have used no plastic, brass, copper or aluminium. Just stainless steel (mostly 304), PTFE washers and Pyrex for the sight glasses. Id quite like to keep it this way if possible. Im not "against" copper as such but don't want the faff with Verdigris forming etc.
Im looking to incorporate HERMS using a pump and "loc-line" style flexible coolant hose for recirculation but with regards to the coil I have a few questions:
1 - Does anyone know where I can source either 10mm / 12mm / 1/2" OD stainless coil around South Yorkshire / Sheffield (or mail delivery for reasonable price)?
2 - If not, would re-purposing a 5/16" (approx equivalent to 8mm OD) stainless steel coil from "that Chinese version of Ebay" be reasonable or too narrow diameter for this purpose
3 - If not, would copper 8mm be reasonable?
4 - I will use left overs for immersion chiller coil so what sort of length of HERMs coil would be reasonable for 10gallon batch?
I have searched many forums and websites and found some info but not for these exact questions!
Cheers!
Joe
Im in the final process of setting up my 10gal brewery and could do with some advice for HERMS. I have a 30l 3kw Burco boiler for HLT (a little small but I find I can top it up and maintain temp while adding strike water to mash tun), 67l Igloo cool box mash tun with bazooka style filter (SS flexible tap connector braid) for batch sparging and a 70l stockpot for boil kettle.
With sight glass, thermometer, all valves and fittings I have used no plastic, brass, copper or aluminium. Just stainless steel (mostly 304), PTFE washers and Pyrex for the sight glasses. Id quite like to keep it this way if possible. Im not "against" copper as such but don't want the faff with Verdigris forming etc.
Im looking to incorporate HERMS using a pump and "loc-line" style flexible coolant hose for recirculation but with regards to the coil I have a few questions:
1 - Does anyone know where I can source either 10mm / 12mm / 1/2" OD stainless coil around South Yorkshire / Sheffield (or mail delivery for reasonable price)?
2 - If not, would re-purposing a 5/16" (approx equivalent to 8mm OD) stainless steel coil from "that Chinese version of Ebay" be reasonable or too narrow diameter for this purpose
3 - If not, would copper 8mm be reasonable?
4 - I will use left overs for immersion chiller coil so what sort of length of HERMs coil would be reasonable for 10gallon batch?
I have searched many forums and websites and found some info but not for these exact questions!
Cheers!
Joe