One note of caution, he describes removing the lath and plaster and inserting eps insulation. It didn’t mention if he did this, he might have done, but it’s important to have a continuous taped vapour barrier on the warm side of the insulation to prevent water vapour from passing through, condensing on the timber structure and causing it to rot. Also ventilate the cold side of the insulation or a least have a gap to form a capillary break with the cold outside wall. I’ve seen a few badly done insulation jobs in timber buildings that have needed floor joists and studs cut out and replaced. It only takes about 15-20 years.