Hi Blue. I never used rods. I installed a LLAMS height controller instead. I also have an IIDTool, which I am holding on to since the guys at GAP Diagnostc say they will support the new Defender soon, but never used it for suspensions height mods, only calibrations and other diagnostic stuff. The LLAMS module is pretty slick as it allows you to modify EAS height on-the-fly, at the twist of a knob: -30 mm, 0 (standard height), + 30 mm or + 50 mm above (or below) any selected height you are in. So, that would work perfectly for your intended use as you can just flip the switch to + 30 mm while in standard height, and drive at any speed you want without ever touching the stock suspensions button. When you are out of the dirt road, flip the switch back to 0/off, and away you go. Or, flip the switch to + 50 mm while in off-road height to basically achieve extended off-road height manually, without the car needing to become high-centered first. Pretty sure Graeme Small in Australia is still selling the device, which is very easy to install as the box connects to the EAS module - below the driver's side A pillar - with a supplied harness, and the switch can be installed anywhere you want (I installed mine on the sterring column, opposite side of the power steering knob.)
Only disadvantage of the LLAMS is that, if you need to recalibrate your suspensions with another diagnostic tool (such as the IIDTool) for any reason, you need to remove it from the picture as the calibration will fail otherwise. However, LLAMS will supply a null plug to temporarily connect to the box, which will in effect disable the module without the need to unplug harnesses and stuff.
Not sure if this forum allows external links, but here is a thread about the LLAMS height controller on a different forum:
https://www.landroverworld.org/threads/llams-height-controller-added.23853/
Manufacturer's web site, they ship directly to the US and offer great customer support:
https://llams.com.au/
It's only money, anyway.