Ok, I will try this again without mentioning any brands of product. Apparently that was my previous sin resulting in my post being dumped.
I am looking for a few answers for installation of 3/8" x 3" Brazillian Mesquite over an original hardwood (presumably oak) floor (2" wide strips). The original floor was nailed (round head sinkers) into the joists by a previous owner and covered with carpet. I have purchased 3/8" x 3" prefinished Brazillian Mesquite and will be installing it in the entry of my home (approx. 80 sq.ft. The location is So. Cal about 20 miles from the ocean (if climate makes a difference). The house has a raised foundation.
Now that the preliminaries are done, I will ask the questions.
#1) I have been told (by the salesman) that I need to use a stapler,although I prematurely purchased a -----nailer cleat nailer on eBay. I am reading from the posts that stapling holds better. Can/Should I use the cleat nailer or is this a mistake specifically for 3/8". Also I have seen stapler crown widths from 3/16" to 1/2". Which is best for my application?
Almost all references on the web are for 3/4" hardwood but I don't want to live long enough to refinish this floor once, let alone 7 times.

#2) Should I run the new material parallel or perpandicular to the original hardwood? I will obviously hit the joists better on every board if parallel, but if the original is tight, does it matter? I am concerned that I may be hitting a lot of the old nail heads if I try to run it parallel.

#3) Do I really need a 3/4" expansion gap all around in this climate? That seems huge, especially for 80 sq. ft. Can I reduce this safely or should I maintain it?

#4) I hate the idea of face nailing the first and last rows on a prefinished product. Can I just face nail the outside edge (under the trim) and manually shoot the tongue at a 45 degree until there is room for the nailer to be used normally?
Any help from those "in the know" would be helpful.

I am starting to get a complex here. Are my questions so stupid that they don't deserve a response, or are they so perplexing that nobody has a good answer?

Dirk, I hate to try to advise people on which fasteners to use on something I have not installed before . You need to contact the mfg. on what they recommend using. Install it perpendicular and don't worry about hitting the joist, it won't happen anyway. If you hit a nail the staple will fold up or come back thru a board. Thats not a big problem.

Is this a solid or engineered wood? It matters, and does the mfg. say to leave that much expansion?

You can blind nail the starting rows without having to face nail everything.