Tommy,
If you can get your hands on Beth Gilgun's book, "Tidings From the 18th Century", do so. I would reccomend this for any one that does hand sewing. Beth is highly regarded as a person who knows her craft and is used quite often by researchers as a resource looking for information on clothing and sewing techniques of both the 18th & 19th century, she has worked for the smithsonian on several projects in the past regarding clothing and it's construction. Hand sewing (technique) didn't change much from the 18th through the 19th century.
For me any seams I sew, I use a backstitch, usaully 12 to 20 stitches per inch depending on the material and what I am making. That was the most common stitch to use then for general sewing. To end my stitch, I use a back stitch lock stitch. They also used the running stitch, overcast stitch and whip stitch, yes, they were used for some sewing, but primarily for basting, hemming and finish work. Do stitches per inch matter? Well, if you are going to the trouble of sewing by hand and want to create something that existed during the era you represent, spent money for a pattern and material, yes they do matter, and more stitches per inch (close stitches are very stong) are hard to tell from machine sewing.
References
Bradfield, Nancy, Costume in Detail: Women's Dress 1730-1930
Kalm, Peter, Peter Kalm's Travels in North America
Martin, J.P., Private Yankee Doodle
Montgomery, Florence, Textiles in America, 1650-1879
Neumann, George C., and Frank Kravic, Collector's Illustrated Encyclopedia of the American Revolution
Most of the above reference materials/books can still be found on the internet, I think.....
Bill