Ho .. The only thing you are gonna trash with those tyres, as you say you're gonna do another 1000 miles on them, on a track day, is your bike an poss yerself.
Although you think a balding tyre may look like a slick, I assure you its nothing like one.
A slick tyre will have a decent depth to its smooth surface .. unlike the WORN OUT tyres you have on your bike at the moment.
To maintain a decent grip on the surface you need heat .. .. as you have worn away 90 odd % of your tread, the tyres will NOT heat up to give you the grip required on a track.
As the tread wears down it is less able to distort and spread around the contact patch and as such, is less able to grip the surface than a new tyre. And as such a worn tyre suffers as much from the lack of tread material as it does from the reduced depth of the tread grooves.
In other words mate .. chuck them away, fit a new set and benefit from the strength and integrity of a new pair.....
Oh yeah, DONT just bung a new set on and tear arse around a track untill you scrubbed them in for about 100 miles.
http://www.bikermatch.co.uk/sites/bm/forum/posts.asp?to...ic_id=7380
Have a quick read of this, and this
http://www.bikermatch.co.uk/sites/bm/forum/posts.asp?to...ic_id=6512
As an aside, the LEGAL tread limit on a motorcycle over 50 cc is 1mm across 3/4 of the width and visible tread over the remainder.
Now that tyre may well be legal !! but it certainly is not gonna give you the grip you're gonna want !!!!
Wheelbarrow's post said it in the first reply to you !!