On Selecting "Alternate" Readings for Pentecost

Here's the lectionary lineup for Pentecost Sunday (May 11):

First Reading:
Acts 2:1–21
Numbers 11:24–30 (Alternate)

Psalm:
Psalm 104:24–34, 35b
R/ Send forth your Spirit and renew the face of the earth. (Ps. 104:30)

Second Reading:
1 Corinthians 12:3b–13
Acts 2:1–21 (Alternate)

Gospel:
John 20:19–23
John 7:37–39 (Alternate)

Note the alternate readings.  How do you go about deciding whether to use an alternate reading in place of the primary reading?  Both the primary and alternate are offered in the lectionary, though for each reading a priority is clearly given to certain readings (Acts, 1 Corinthians, and John 20 passages, respectively).  What criteria should govern my decision to choose the alternate reading?

(Perhaps some of you have few qualms about replacing the appointed lectionary readings for a given Sunday.  I err on the side of sticking with the lectionary, assuming it has an internal integrity and wisdom that I - working as a lone ranger - lack.)

For Pentecost Sunday, I'm inclined to choose the alternate texts for the First and Gospel readings.  Here's my reasoning.

I prefer the John 7 (alternate) Gospel text because the passage from John 20 (the primary text for the day) was included in the Gospel reading for the Second Sunday of Easter - the doubting Thomas story.  To repeat the text so soon just seems repetitive.  Plus, the John 7 text sets up a discussion of the gifts of the spirit and our grateful response - "out of the believer's heart shall flow rivers of living water" - to God's graciousness.  That "grateful response" is something that we Lutherans have a difficult time addressing . . . good ol' Third Use of the Law (of which I'm a fan, though I know many Lutherans do not believe in the Third Use).

We may also choose to read the alternate First Reading from Numbers.  We may tell the Acts 2 story - the giving of the Holy Spirit at Pentecost - through a youth skit to be shared as the opening rite to our Pentecost service.  Plus, I really like the Numbers reading - it gives some deeper context - a prequel, if you will - to the familiar story of Acts 2.

So, what do you think?