Doing a loft conversion - am taking every opportunity to strengthen the roof as I come across it; so the ensuite wall is going to act as an extra roof support wall / knee wall type thing running about 1000mmm parallel alongside the purlin. Whats the best way to attach the timber for this support wall to the rafters at the top? I'm using c24 2x4's. I think I have 2 options, screw the 2x4 straight to the rafters then chamfer the upright struts at the top to meet this on the angle of the pitch, or fit the 2x4 top timber straight into the straight edge of the struts and somehow fit this to the rafters? I'd birdsmouth them but can't figure out how I'd get accuracy across all the existing timbers. I'm sure I'm not being clear here and the answer is obvious. I've attached 2 images of the al;ternatives - the photo is one where the timber is made straight but I can't see how it attaches to the rafters to offer any structural support - and the alternative I've drawn makes me think a chamfered top edge would be weaker as the weight would be coming down at an angle?