Dead space in HERMS coil

I’m about to embark on building a HERMS system with BrewPi products (I’m just waiting for the new variable speed pumps to come in stock before ordering). One of the decisions I face is if I should buy a flat bench top, or build a frame for a tiered system.

@Elco, as far as I can tell from your blog photos and HERMS diagrams, with all your pots on the same level, you must have a reasonable amount of dead space from pump 2, through the HERMS coil up to motorised ball valve 8? Do you have any idea how much this is in L? How do you deal with this currently, do you detach the output hose from pump 2 and let it drain into another vessel to recover it? Or do you sacrifice it for the sake of automation?

I’m building a 33L pot set up, and I’m thinking it might be better to have the HLT raised above the mash tun and boil kettle. If the output of HERMS coil was at the bottom, the wort in the coil (and lines through to M8) would then drain into the boil kettle after sparging.