Kwasniewski takes a laissez-faire position on this question, and that is appropriate, though it may be counter to the mindset of many Latin traditionalists, who will insist upon kneeling as the appropriate posture for certain parts of the Mass, etc.
There is but one further angle to examine: the Problem of Pews. Since nearly every Catholic church in the West is now equipped with pews, usually bolted down for permanence, the topic is far more speculative than what we have discussed heretofore, and deserving of a separate treatment.The two questions are intertwined so I await for the next part of his discussion. There is also the first ecumenical council's prohibition of kneeling on Sundays, but Latin traditionalists think the patriarchate of Rome is above that. And then there are sentiments like this expressed in comboxes and elsewhere:
I like the fact that the TLM has no rubrics for the laity at all -- including posture. It underscores the fact that the congregation (to be blunt) has absolutely nothing to do with the activity of the Mass. The priest offers the Mass. The server (clerical role) makes the responses. The schola (clerical role) sings the chant. None of this, at least in the missal or rubrics, is appointed for the congregation.