On a new build, the answer is a straight yes, because you would position the brackets in exactly the same way as on a battened roof. On a retrofit, when you are replacing the last course of slates, you can’t access the nailholes, so you would need to use the HallHook. On a battened roof the nail holes are determined by the battens. On a sark boarded roof, the nails should be in the right position but they could be in a different position.
If the nails are not in the same position on a battened roof, then the HallHook can’t work effectively as the lap could be compromised.
Per building regulations and the manufacturers specification for that roofing material, but never less than 20 degrees.
SolarFlash is designed to give a maximum 4 inch / 100mm headlap, and is designed for single lap tile layout and double lap slate layout (with slates, the pitch is as per the building inspectors recommendation).
We would never recommend the use of a flat bracket. The main issue we see is that any contact between the bracket and the roofing material will transfer movement in the panels onto the roofing material.