The first thing is that Lassus' falsibordoni use the psalm-tones of the Divine Office, not the more intricate tones used at the processional chants of the Mass (i.e. the Introit & Communion); all of these tones, together with their variant endings, can be found in the Antiphonale or the Liber Usualis. Also, I assume you know this, but for anyone who doesn't, the psalm-tone in these (and, in deed, in most) falsibordoni occur in the Tenor voice, not the Treble.

The tone that you have used is tone 1-D, which is probably the best to use in this situation, since the psalm-tone used for most of the Mode I processional chants ends on D (re). I don't have my copy of the Lassus Edition with me, so I'm not sure exactly how many different endings he used for Mode I : I know he used endings D, g, and f, but I don't remember if he used others.

The second thing is that the versions of the Office tones used by Lassus were those that were current at his time, so there will be variants between the melodies known and used by Lassus and those that appear, 'restored', in the Solesmes books -- Mode IV in particular is different.

I hope that this helps a little.

Just as a side note to anyone interested, in addition to faburdens for the regular eight tones and Peregrinus, there is also an interesting fauxbourdon that doesn't seem to correspond to any known tone that I can think of -- it is certainly an Irregular Tone, very irregular.

As you no doubt already know from reading the German preface, the attribution is to "circle of", but they're still so much more fun than Carlo Rossini's! I've used some of these for Gospel Acclamations:

I completed the Lasso Falsobordoni for all of the Psalm Tones. I am going to use them for a while and make edits as necessary. Please feel free to send me any comments and edits. If you are interested in getting the Sibelius or XML file please send me a PM with your email address as the forum won't let me post it here.