timber frame is a mare ian lad. i done an ewi using a rail system over a milne frame mechanical fix with 20mm cavity space. we had to string top to bottom every 2m distance and every fix had different packers like +or- 1,2,3,5,10s spirit level on every fixx at 250 centres, it took twice as long but i managed to counter charge the wood butchers. i always allow more for timber frames