Hi Flitz,
Go Here For The Video
http://www.e-cigarette-forum.com/forum/tips-tricks/20403-fluval-cartridge-restuffing-video-instructions.html
The Length Of The Straw Will Depend On What Cart You Are Using. Just Remove The Cart Filler, Stick Your Straw In The Cart, Cut Off At The Top of The Cart, Then Pull Out The Cut Straw and Trim It Down A Little, Do As Needed.
I have Some Real Low Probably 3/8" Below The Edge Of The Cart, They Work Fine. Its Experiment & See, No Big Deal. I Have Just Eyeballed The Length Many Times, No Issues.
All My Straws Are Different Length, They All Work Great. I Did Initially Over Fill A Few Carts, But After A Bit It Worked Fine and I Have Not Had One Overfill, I Am Really Filling The Carts Up!
And Hey, If You Don't Like It Just Yank it Out, But Give It Some Time 1st.
Forgot: Never Had Any Melting, 801, 901, 510, Stick & Mini-Pipe
~Keep Vapin~!