You get more contrast if you use more magenta filtering. MAximum magenta (130 or 170, depends on the enlarger) gives pretty contrasty images. I rarely use more then 60.
The exposure time should me so long that the clear film base gives a deep black. Therefor it is a good idea to include the clear edge of the negative in the test strip. If you use a shorter time you get nowhere in you imgae a deep blacl. If you have that deep black, but the highlights are grey, you need more contrast, more magenta.
It may be a good idea to use 1+4 devleoper. This gives arond one grade more contrast.