Ballpoint needle is good.
Knits can be sewn with a straight stitch machine. Lengthen the stitch, Stretch the fabric and sew - for example - if one usually uses a 2.5 stitch length setting (maybe 10-12 stitches per inch?) lengthen the stitch length to 3.0 (or so).
For methods, Google: Stretch and Sew
Practice on scraps.
Knits vary from little or no stretch to almost doubling in width or length. Generally, the fabric is cut so that it is more stretch going around the body.
Most knits do not ravel - check to make sure it isn't a "runner" - like nylon stockings or pantyhose - so hems only need to be turned up once.
Generally, the seam allowances are only 1/4 -3/8 inch .