How to weight the fin is an area where personal preference and how you use it play a huge role. My suggestion is use the fin a while and see how it works for you. If needed, add the appropriate floatation. A lot of it has to do with technique,body fat,wetsuit, having the right size neck weight (neck weight is needed for this fin), and how fast you swim. Very good technique, swim fast and have the right neck weight and a thick suit on your legs and floatation might even be a negative.
I only know of one other user besides me who felt the need to add floatation. My use is often like yours, so I would not be surprised if you needed it. My solution, (foam covered with fiberglass) works, has minimal cross section, but has durability problems. I suspect that Ron's wood solution will work better. He will probably have his out soon. If not, its no problem to make your own or have a woodworker do it for you.
To your specific questions
In any case, it won't be a big enough problem to affect your purchase decision.
If you need floatation and don't correct it, tail heavy becomes annoying after you begin getting used to the fin and will make you mildly uncomfortable, with associated reductions in dive potential. The gains from the fin will probably offset the negatives, even if you don't correct it. In my case, I like the fin, tail heavy or not, but it is much better with floatation.
Oh yeah, in the pool, going slow, floatation helps keep the fin from beating up the pool.
Connor
and am planning on buying my first monofin (traditional one)....but now some people in this forum changed my mind and am currently looking at the x20 due to its portability and other positive features as i plan to travel a lot. 
