Dmitri Lytov told me that:
... the 1st and the 2nd functions are different by QUALITY, not just by quantity. In fact, the numbers of positions in the Model A do NOT reflect the "weight" of corresponding functions...
Therefore, making a test based on Model A is problematic.
I think that making a test on I/E, S/N, T/F, j/p is also problematic.
I think that the best way to determine your type is to patiently read through the type descriptions here:
http://www.socionics.com/prof/prof.htm
and to see which description fits you the best.
I'm considering making a summarized description of each type, somethin like the following from an MBTI site:
http://www.personalitypage.com/high-level.html
Please tell me what you lot think.