Staff Rota

I have 2 members of staff that share a rota.

The Head Chef works 20 hours per week 4 x 5 days, or could work 5 x 4 days if it helps the shift pattern.
The Assistant Cook works 16 hours per week 4 x 4 days

Wednesday is Admin day for the Head Chef, so both her and the assistant chef need to be in.

I need a rota based on a 2 week schedule if possible that allows both to work their allocated hours but do alternate weekend shifts where possible.

Really struggling to get my head round the shift pattern.

Sorted I think

This is a 2 week rota. Starting Sunday this gives alternate weekends off and alternate Mondays off. Wednesdays are fixed because both are in.
Using this pattern the only days that are flexible are Tues, Thurs and Fridays.

By adding a day to 1 shift and removing from another keeps the 20 and 16 hours weekly shift pattern based on Head Chef 4 x 5 Hours and Assistant cook 4 x 4 Hours.

1st Week starting Sunday Chef does Sun, Mon, Wed, Thurs and Assistant does Tues, Wed, Fri, Sat
2nd Week Chef does Tues, Wed, Fri, Sat and Assistant does Sun, Mon, Wed, Thurs

Sort of, but your example misses the point that both need to be in on Wednesday. I should have also mentioned that they do alternate weekends and Mondays. This leaves the flexible days as Tuesday, Thursday and Friday which can be swapped as required.