"Lesser Kan & Li" (LKL) and "S.Biel's Fire & Water Technique" (SB's FW) overlap, and bear some comparison.  Each has its own strengths over the other - that are important to understand.

SB's FW is gentle, safe for beginners: it's easy enough on subtle anatomy that it can be done every day.  This is due to the fact that the way SB's FW mixes fire and water does not create a suction, no pressure.

Additionally, it brings balanced compassion energy distinctly, repetitively, and deeply into the home of both water and fire, so that any disharmonies that are living there can be healed at their source.  SB's FW thus does a better job of healing fire and water disturbances at their source (read on for more about this).

The way that fire and water are coupled in LKL (the inverted hooking around, plus the maintaining of only a partial intersection of the fire and water spheres) creates a suction, that strongly draws more energy into the cauldron (the center of the coupling).  It's great for drawing lots of energy in, condensing it, and for creating a viable cauldron.  Additionally, it tends to draw together (and potentially repair) your subtle aspects... strands of your being that might be dislodged, loosely straying about, are brought into integral cohesion with your form - by the power of the LKL suction.  The suction power has some very positive aspects.  The suction power also has the danger of being employed to excess.

To take best advantage of LKL you should have some practice in accessing heavenly and earthly energies, that the LKL suction will tend to draw in.  There are any number of ways to develop this.  In the standard HT progression, the Fusion of the Five Elements II practice addresses the opening of the thrusting and belt channels (though, personally, I find the standard HT Fusion II methods of opening the thrusting and belt channels to be cumbersome).  The version of the microcosmic orbit described in this website triggers aspects of heaven-earth integration, including spontaneous opening of the thrusting channels and leg routes. Various static and/or moving standing practices, including internal martial arts, help to develop this facility.  Yi Swallows Chi can also assist with opening to these energies, and can also assist with relieving excessive build-up of pressure.

Respect the fact that LKL's suction will probably create some pressure in your body:

You need to be careful not to practice LKL too often, which could create more pressure than your body is ready to deal with effectively.  It's my humble opinion that daily practice of LKL is dangerous, except perhaps by those that are really quite far along in their cultivation.  Practicing LKL once, twice, maybe three times a week, is plenty.

Another aspect of dealing with the pressure is to be attentive to your practices that circulate, distribute, energy through out your body.  Activation of the five elements.  The microcosmic orbit.  Yi Swallows Chi.  Stretching.  Aerobic exercise.

LKL doesn't necessarily harmonize fire and water at their sources.

Meaning, LKL does take fire and water and mix them in the cauldron - creating a balanced steam.  So, in one way, you have created balance.

However, you might do LKL but direct the steam elsewhere besides to your heart and to your sexual palace.  For instance, there might be a sexual disharmony residing in your sexual palace that might not get directly addressed and healed by doing LKL.  Although you've "balanced the energies" in the cauldron, you're still left with an active sexual disharmony that will continue to generate trouble.  Creating balance in the cauldron does not necessarily bring harmony to the sources (fire: your heart, and water: your sexuality).  Be aware of this fact and you'll save yourself mistakes.

Those are my thoughts.

Hope that they are of help.