Here's a better pic of the WFL snare stand I shortened up to allow me to use my 12X15 marcher as a FT.
I only cut a section off the bottom tube. I don't remember exactly how much but made some measurements and kind of figured out how much I needed to cut off the bottom tube about 6 to 8 inches I think (the difference in depth between a 5 inch snare and 12 inch marcher).
Had to first remove the clamp assy on the top of the bottom tube used for tightening. Then I used a pipe cutter like plumbers use on copper pipe to cut off the tube and then reinstalled the top clamp assy. It was pretty straight forward. You should be able to do it no problem assuming you have or can borrow a pipe cutter. You might be able to use a hack saw but risk deforming the tube - I wouldn't advise that. Anyway it worked out great for me I thought.
One other thing to note. By making the bottom tube shorter you will not be able to fold up the stand all the way to fit in your hardware bag if you plan to gig out with it. You may consider that a minor or major inconvenience - I don't know - just something to to consider ahead of time.
Doug