The thumb screw for the front brake reservoir door is the same knurled aluminum screw that attaches the dash fascia (instrument panel) to the oval dash. These should be available through suppliers referenced on this forum. The thumb screws for the 2 fusebox covers are more difficult to find. I needed 1 thumb screw, and after searching for about 2 years, I had a new one made by pouring a mold using my existing screw as the prototype. Turned out great. Sorry I couldn't be more help - maybe someone else has a source for these thumb screws?
I see that Mike Dunn of MadEnterprise (http://www.madenterprise.com/) has these They fuse box cover thumbscrews are $17 http://www.madenterprise.com/catalog/rubberandplasticparts.htm PLASTIC FUSE BOX COVER FITS MOST 250'S, DINO 75.00 / ea. KNURLED, PLASTIC HEAD SCREW FOR ABOVE 17.00 / ea and while in the past I believe I've seen him sell the front brake reservoir access door thumbscrew, I can't seem to find it on the website now, better email him to be sure. Hope this helps, Scott
Interesting site, very expensive though!! Washer bottle Foredit $380 same in the UK around £50 ($100) sorry cannot help on the screws required, i believe superformance are remaking some of these very shortly. Watch there web site as they have loads of new items coming through for the 246. The foam for the seats are a revelation to owners redoing there seats.