Hi Leon,
the form loads much faster when using XML files. Basically you are just building the XML via code the way you are doing it.
I don't get exactly what you mean by " adding the necessary SDK code" since you are just shortcut the creation of the form - everything else stays as ist is.
I would strongly recommend to use B1Studio to create the forms - it is simply the easiest way. As for the dimensions and positioning I stay with what I said in the other thread.
Afaik you can't use formulas in integer fields - but you can of course modify your xml before adding it. The usual approach would be to calculate needed properties ( left,top, width..) when from is resized or loaded.
ARD creation is the same.
I don't know about your project, but you should definitly have a look into the B1Studio template for Visual Studio ( 2010 or SBO 9.1PL3 = 2013 ). If it is applicable ( it has some flaws ) in your case it would simplify your life a lot.
regards,
Maik