Autosuggestion 101
1) It works as well as you truly believe (in your heart <3) that it will.
2) The more you practice, the better you should get at it (if you believe)
3) Being too tired (mentally) will dampen the effect
4) Going through the motions of it will make it less effective
Sounds like a good tech. Really concentrating on it can help, but if you just write it down mindlessly, you will be screwed. I am not a fan of writing, because it is slower than typing. I am not a fan of typing all that out, since I like to spend my typing time writing books and being on DV. ;) But concentrating on a mantra can help you out any time throughout the day, how you concentrate on it (visuals, writing, typing, eating) is up to you. Good luck on your autosuggestion journey.
Computer monitor is bad for recall, and if you have any insomnia you should stay away from it 1 hour+ before bed time (sleep is important for LDing I am pretty sure). But for some, it isn't as bad as for others. Lots of things effect recall and awareness in a dream, but you can't stay away from all of them or you will be a monk. ;) I like to find out which ones effect me negatively more, and the ones that effect me positively more, and stay away from and stay close to those. Something I believe varies from person to person.