Hi @line-weight
Luka may help more on this but below are a few comments,/answers
*The workflow is up to you, the seminar goes through what I think is ideal but feel free to improvise
* Q1 Multiple mullions (muntins) are poorer thermally - the less the better
* Q2 Average out the volume in the block
Q3 - unsure
I wouldn't use this for Building Regulation submission - SAP only for this
Mark