2. The 'nodes' are the little joints up and down the length of the flower spike. You can cut them just above the third node from the bottom if you choose to do so. I generally do not practice this. Instead, I cut the spike one inch above the plant and let the plant rest and grow so that I get larger flowers on the next spike. It is really personal preference.
3. Newer buds will be smaller. Patience is the key with orchids. They will continue to grow if given the right conditions. The smaller buds opening early could be from moving the orchid from one location to another. Something probably out of your control.
Finally, about previewing a post. To preview your post you must do one of two things. If you are using the 'quick reply' box at the bottom of the page, then you need to click on the 'ADVANCED' button. If you actually lick on the 'REPLY' button below a post or the 'QUOTE' button within a post, you will be taken to the main reply window and below that will be a 'Submit Reply' and a 'Preview Post' button.
Best of luck!