1. Unfortunately, the text notes do not (yet?) support ink. But your need could be met by using a Sketch attached to a branch label. The sketch box area will take any marks--text or pictures--that you can make with a pen. It won't subsequently convert your text, but it can function as an attached note area.
2. Tools/Preferences/Tablet PC lets you specify the ink input field in pixels. Bump it up and write the same size, as many lines as you like! (In other words, you don't have to obey the line guideline in the input field.)