@Jake I don't know the answer to your question as I have never used microbore.
The boys from Aquadapter were experimenting with smaller diamt pole hose a few years ago.
I found this correspondence from June 2102 from Aquadapter that you may find interesting (albeit a smaller length of pole hose);
We have done some testing with it, however, we would also like some confidential feedback from more users before it goes on general sale. It is of the same materials and specification as our dark red hose (which some of you tested for us, thanks) but is 6mm Outside Diameter and 4mm Inside Diameter* (current hose 8mm ID/5.5mm ID).
Flow Controllers
These should work with a smaller bore hose with little issue.
You will need to recalibrate the controller DE setting after fitting the smaller bore hose.
Turn the flow rate down (see Pumps).
If possible, avoid any extra angle fittings on the hose which will increase pressure. Ideally there
should be a straight run from the pump to the Aqua-dapter / Brush Head.
Please let us know before using the hose with a Williamson Varistream.
Pumps
It is to be expected that a smaller bore hose will increase the pressure in a system giving a faster
jet at the brush head but reducing the speed of the pump.
In theory the pump works at a lower speed to generate the same flow at the brush (hence the
note above about turning down the flow rate on the controller).
Where no controller is used the effect of the smaller bore hose may be to increase the pressure in
the system. With the pump working 'flat out' the effect of temperature and hose wall expansion
(see below) could put additional strain on the pump as it has to work harder to generate the
pressure and force the slow moving water.
Hose Wall Expansion / Ambient Air Temperature
Hose wall expansion can be dependant on the stiffness of the hose wall. A soft hose wall would
expand a lot so slowly building pressure whereas a hard wall (as our hose is) will build pressure
quickly. With a soft hose wall the water could take slightly longer to begin flowing.
Ambient temperature effects hose wall expansion and the viscosity of the water.
Cold water, near or at 0°C, flows more slowly than warm. Lower temperatures also effect hose
wall expansion rate as a cold hose expands more slowly. Our hoses should be more consistent in
warm and cold weather (or warm/cold water) due to the construction and materials used so,
although any hose will be affected to a certain extent, on our hose the effect should be minimal.
When using a flow controller re-setting the DE calibration should take care of both these effects.
Because I use a Varistream I was excluded from the test experiment.
In the early days when suppliers first started offering minbore and microbore hoses in place of 1/2" garden hose, Williamson pumps wouldn't guarantee their Shurflo pumps if we used those sizes. They said it created extra strain on the pump - they should know. We chose to go the minibore route as the hose wasn't as small as microbore and still easier to manage. I decided that we would bear the cost of our own pump failures as using minibore was a major step forward.
Alex Gardiner didn't rate Shurflo and sold Flojet which he maintained was a better pump. He believed that Microbore was the way to go from what i remember. With experience we never had issues with pump failure, only with pressure switch failure. The analogue controllers Varistream first introduced solved that problem and allowed us to regulate our water flow. I maybe wrong, but I don't think at one time Alex used to use a flow controller, so found the microbore restriction gave a good flow rate at the brush head which he was comfortable with.
Again, I maybe wrong, but Alex was never an advocator of 3mm jet sizes, he always recommended 2mm.
Is that for jet washing?
