I think you’ll find a na k3ve with a light flywheel will give you the low end immediate response, and be easier on boxes.
It’s been years now since I’ve done a Dai disc brake conversion. All the ones I did were on L200s, but the process should be similar. This is a little info somewhere in the “Not quite Track” thread. You would need either Daihatsu Appluase rear callipers, back plates and discs or some Mazda Mx5 callipers are the same casting but you’d have to check the MX5 disc for fitment/offset and make some backing plates. For the hand brake you can use the original cable but a couple of adapters need to be made on a lathe.