After equal amounts of procrastination and trepidation, I finally installed a rubber keyboard in one of my CF-19's since I did not want to bog down my CF-30 which I use daily. I tested myself on the previously-mentioned website
I have gone from 112 words per minute on the emissive chiclet down to 48. Now mind you that my 112 wpm was done on the CF-30 which is easier to type on than the 19 and I have a few scotches down the 'ole gullet. It was a chore, and I'm thinking of getting an additional CF-30 (or save some dosh for a 31) to install my other rubber keyboard and use it in more extreme situations.
Then again, this little CF-19 can be my extreme situational device. I just despise its battery life when I'm in the wilderness which forces me to lug additional batteries. So there you have it, a 58% decrease in typing performance.