Yep if you get a big gash in a tyre, the goo is no use. I hit a piece of truck tyre at night, that gashed the tyre, so I was glad I had a proper spare.
Even if you have AA RAC etc, if they tyre is knackered and its out of hours, you are stuck.
I looked at the options, space saver is £170 from HH. So i bought a 16" steel wheel and cheap new tyre from www.mytyres.co.uk for £115 delivered.
Same size as on the base ES spec Accord 205/60/16 I think. So its compatible with 17" wheels, as the diameter is the same.
Once you take the sealant, and pump out and the foam insert, the wheel fits in the tourer boot fine. I bought the bolt to screw it down also.