So, how to model Solar and Wind hourly variability or variability model that adjusted for selected time slices

There's a variable for each transformation process called Maximum Availability. That variable can either take a simple percentage number, in which case it limits the production in all time slices to that value, or you can specify a time-series expression that specifies the maximum availability in each time slice. You can use that to limit how much is produced from (for example) solar in different seasons or at different times of the day See the screenshot for an example.

You can use various functions to specify this, but probably the most useful is the YearlyShape function that lets you refer to time-sliced values stored in the General:Yearly Shapes library.

Hope this helps!

Charlie