You can specify the partition length in the scaffolding tab of the scaffolding settings dialog.
Location of Partition Length Setting
Select the scaffolding for which you want to change the partition length and click the right mouse button. Click Properties from the right-click menu that opens.
Enter the scaffolding settings dialog.
Enter the new length value in the partition length box.
Your partition length will change according to the value you enter.
Scaffolding view before changing partition length
Scaffolding view after changing partition length to 150
Scaffolding view after changing partition length to 300