PowerShell, 168 125 122 bytes

$a=(,' '*24+'
')*16
0,8,8,88,8,88,8,8|%{$i=$o+=$_
'&$:&8%$%6%&%5%&%6%$%8&:$'|% t*y|%{$i+=$_-35;$a[$i]='\/'[$i%2]}}
-join$a

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PowerShell, 168 125 122 121 bytes

$a=(,' '*24+'
')*16
0,8,8+(88,8)*2+8|%{$i=$o+=$_
'&$:&8%$%6%&%5%&%6%$%8&:$'|% t*y|%{$i+=$_-35;$a[$i]='\/'[$i%2]}}
-join$a

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The script creates the array of 400 chars and renders 8 diamonds started from positions 0,8,8,88,8,88,8,8.

• The string '&$:&8%$%6%&%5%&%6%$%8&:$' contains offsets for the rendered symbols.
• The expression |% t*y is shortcut for |foreach-object toCharArray

The script creates the array of 400 chars and renders 8 diamonds started from positions with intervals 0,8,8,88,8,88,8,8.

• The string '&$:&8%$%6%&%5%&%6%$%8&:$' contains the intervals of offsets for the rendered symbols.
• The expression |% t*y is shortcut for |foreach-object toCharArray

PowerShell, 168 125 bytes

$a=(,' '*24+'
')*16
0,8,8,88,8,88,8,8|%{$o+=$_
&{'&$:&8%$%6%&%5%&%6%$%8&:$'|% t*y|%{$i+=$_-35;$a[$o+$i]='\/'[$i%2]}}}
-join$a

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• The expression &{...} creates a new context with new $i variable. It is shorter then $i=0;.

• The string '&$:&8%$%6%&%5%&%6%$%8&:$' contains offsets for the rendered symbols.

The script creates the array of 400 chars and renders 8 diamonds started from positions 0,8,8,88,8,88,8,8:

PowerShell, 168 125 122 bytes

$a=(,' '*24+'
')*16
0,8,8,88,8,88,8,8|%{$i=$o+=$_
'&$:&8%$%6%&%5%&%6%$%8&:$'|% t*y|%{$i+=$_-35;$a[$i]='\/'[$i%2]}}
-join$a

Try it online!

The script creates the array of 400 chars and renders 8 diamonds started from positions 0,8,8,88,8,88,8,8.

• The string '&$:&8%$%6%&%5%&%6%$%8&:$' contains offsets for the rendered symbols.
• The expression |% t*y is shortcut for |foreach-object toCharArray

First render steps: