There's a thing called RediSpace by Mead, which pretty much does the same thing, but would be too small for a 6 year old. You might want to check out what else they sell under their heading of Multisensory Early Writing Program.
I can't remember if Mead makes it, but we found similar paper with larger room to write when our dds were younger - I think we found it on the shelf at our local big box store
Also, fwiw, my dd who had vision issues used to just completely not space anything. Her spacing improved dramatically after vision therapy. I wonder if even though your ds' vision challenge is perhaps not great enough to absolutely require VT (per what the dr told you) - if it wouldn't be worthwhile to invest in it anyway if you can? I imagine if he's even straining just a little bit to track his eyes and head are getting tired quickly, and while he may be reading well, he might not be reading anywhere near as well as he could be if his eyes were 100% tracking. I also know that our dd used to have an eye shut off - basically the brain flips a switch and the child starts seeing out of only one eye - that happened when she was tired from vision strain. You could tell when it happened because she'd tilt her head to read.
polarbear
