Start workday,Gantt chart

[daredan]

Hello,

I am trying to create a fully flexible planning time-table for monthly tasks being performed ('planning' sheet, row 40:82).
All tasks are due on a specific working day (column H) and based on the month/year selection the effective deadline dates are calculated in E4:F38 in that sheet.

Everything is working nicely so far, however I'm having a bit trouble on the fine-tuning part:
In order for the project timeline chart (Gantt-chart) to properly visualize on the 'Gantt' sheet I need start dates and duration. Duration is a manual input and the start date (column C) is currently calculated =[@Deadline]-[@Duration]. However this simple calculation would include weekend/holidays, which results in an incorrect chart result.

Just to illustrate using row 43:
The task 'BPC open for input' is due on Monday 03-Feb-2014, 00:00. The duration is 2 work days. The current calculation for the start date in C43 is Saturday, 01-Feb-2014 00:00. However the correct start date should be 30-Jan-2014 00:00 as weekend shouldn't be counted as workdays. So I'd like to visualize on the chart that the task lasts 2 workdays, however lasts for 4 (2 days work, 2 days weekend) days in total.
Additionally I wonder if for 'cosmetic' purposes somehow weekend or holidays could be included in the plot area (currently I just used manual text boxes for illustration).

I hope I could comprehensibly explain the issue and feel free to use what I built so far for your own purpose. I think it's one of my more fancy developments as it'll save quite a bit of time of planning monthly recurring tasks.

Brgrds,
Daniel