I am not a contra player, but I have always enjoyed the instrument. Reed shape can also help, I use the Rieger K2 shape an I feel I can get a nice dark sound with it over the K1 shape, it's a chalice or cup shape, like a baroque or Mechler(?) shape. I think Fox has a similar shape that is narrower that requires less air. I quite often will switch reeds for a work, lighter ones for quieter passages and heavier ones for more power. I take the sides way down on the light reeds to keep any surface noise or extraneous buzz or flap out of the sound if I make a crescendo, it also gives me a nice focus to those low notes for a nice dark, but pure sound. I find it also helps to have less slope in the scrape, more gradual, less like a bassoon reed, but that might be personal preference. I used 3 different reeds for the contra part on the Adams chamber symphony performance we did last year, although it was more about greater volume and high range. You can also use the low register keys to help the pp range of the middle register. In Carmina Burana there is a rather difficult pianissimo movement in the mid range that I remember playing with all of the low keys closed, maybe starting from low F to Bb, I don't remember exactly.
Principal bassoonist, Orquesta Sinfonica de Galicia, A Coruña, Spain. Bassoonist, bassoon dad, bassoon husband, bassoon uncle, bassoon brother and bassoon son.