Seeking advice on Personas Development

I got invaluable help from those wonderful articles by Former Member and@Tobias Queck provided valuable insight about Personas. I wish to thank them and all contributors for providing help, guidance and ideas.

Now moving to the point

As I will be doing more and more complex work using Personas, I thought it is time to be aware of the best practices for Personas. If such set doesn't exist, I am glad to create one through this discussion. I have read Former Member already discussing in his post Personas idioms

1. I learnt following things in my 10 days with Personas.
   1. Keep it simple. It can be extremely difficult to do things in a single script. Break your scripts in smaller chunks and proceed.
   2. Break IF condition is chunks. First handle the negative conditin and then proceed with others, each on a separate PUSH.
   3. If you are processing bulk data and exploring selection, then keep a stricter SELECTION criteria. I noticed that while using ME2L, with a larger date range the browser (IE 8.0) took forever to load, especially customized flavor.
   4. Insert Refresh Screen before COPY and IF statements
2. Problems I am facing
   1. How to evaluate whether a requirement can be achieved using Personas?
   2. How to handle errors? The trick I am using is read here on SCN and that is, Check for the status bar. However there is no way to differentiate between warning and error messages.Everytime if a message pops up, I just come back to main screen showing it to the user. I tackled some messages by removing ENTER and hitting the action buttons instead, but still no way to identify message type and choice proceed in case of a warning message makes thing bit tough.
   3. Checking existance of data - Again reliance on screen fields. I check whether the control is available. If it is not assume that value doesn't exist. However, this can be tricky in scenarios like reading PO statuses. In some case I see Delivery and Invoice status as 3rd and 4th and sometimes they are 2nd and 3rd. How to tackle similar issues?
   4. I am not happy about the current problem with checkboxes. I was performing some conditional scripting in PA30. I had copied checkboxes values in variables but when I tried comparing them, It failed totally. Finally I checked there values on Presonas screen and populated variables using JS, and it worked.
   5. Dealing with tables or multiple rows can be tricky. We have no direct way to paste table in Persona screen.

I will appreciate contributions, inputs from other members.

Sincere thanks for all the help.