Well I'm not the tallest person in the world either, but I am 6 foot and I dont have to crouch down.
I just hold onto the handle with my right hand (am right handed [except when writing]) and drop my hand and right shoulder down a bit and it rollers - no problem.
The slit is quiet narrow on the wonderwand anyway - just 3mm. I reckon a glide may not actually fit.
I have a "standard" wand and the slit measures 7mm.
Try Cleansmart at Nottingham, they sell the Wonderwand and also glides I think.