In Technical Documentation, I would prefer to differentiate the word - Select and Choose based on the following contexts:
I will use Select when I'm directing the user to select from a list available.
For example: Select the option from the drop-down list.
I will use Choose when I'm directing the user to choose an option from the user interface so that he gets done his task.
For example: Choose the Finish option to exit the installation.
Basically, the difference is that - use the word Select when there is a List, or Drop-Down, check box selection, and Radio Button and user can select any those freely as per their wish to execute the task.
And, use the word Choose when you are conveying the user to do a specific action to achieve their objective.