I've tried different systems, but the one I like the best is the Claude Gordon system.  I augment this with other books (like Mark Van Cleave's Max Practice, Clyde Hunt's "Sail the 7 C's", Eddie Lewis' "Daily Routines", etc..)

> 1) How much practice time each day was devoted to the course?

Hmm, 1/2 hour to an hour at least...

> 2) How much did the course increase your range?

Uhh, about a Perfect fifth...  But more than increasing range, it stabilized what I already had.  I don't look at the Gordon method as a "range" method per se, but rather a method to teach you to play the trumpet more efficiently.

> 3) Did the approach have any adverse affect on other aspects of your playing?

No, but it can.  You must balance your practice.  If you are practicing a lot of extended arpeggios, balance that with softer playing as well...

> 4) Do you continue to perform the exercises from the course?

everyday!

> 5) Do you still have the added range you achieved during the course?

Of course, if not, why do it?
 

- -Donovan-
Tulsa Band Instruments, Inc.
http://members.tripod.com/~tulsaband