Always happy to help, I'm still revising my pages a bit, so most links can be found easier.
www.geocities.com/x_canuk/siteindex.html

I did drill out the bottom of my cupholders, you can see the hole on the gps page. The cup holders are shallow, so without the bottom, it will hold cans or a thermo's mug more securely.

Back to the topic, the prime advantage to using a laptop, you have a keyboard, mouse & screen all secure, no wires, and takes literally seconds to install and remove.