Finger Stretching Techniques?

The size that I am most comfortale with is a concert but I really want a tenor due to its fullness and the amount of frets it has. Doing simple chords on a tenor like C,D,G,A,F, etc. are a peice of cake but when it comes to chords that require me to stretch my first and pinky fingers 6 frets apart, it hurts a little. I can almost get it but it buzzes a little. What are some good stetching techniques that will allow me to adjust with or without the ukulele. (Without would be preffered.)

Note: I am used to a soprano ukulele.

Here's some:

http://ukuleleunderground.com/2008/05/uke-minutes-16-finger-stretching-warm-ups/

http://www.fretjam.com/finger-stretching-exercises.html