When I last ask about diam of sanding blocks what kinda you use,
diam varies quite much for same pitch reed.
how does the diam of inner curve =sandingblock , effects to tone…
the smaller-brighter, bigger- dull or..
I just make few reeds with evertjan’s method, nicely in tune , good back d and good scale
overall, but somekind "dull "sound . How to manipulate the reed ,to get free vibrant ,more characteristic sound…
The ‘dull’ tone you mention can also be caused by slips that aren’t sanded/scraped thin enough. I know that if you use a larger diameter cylinder, one of the effects is to have a reed with very low elevation when tied up. THis forces the use of a bridal to open the lips up and in so doing squeezes the edges of the slips together making a better seal - …or so I’m told.
Your mileage may vary. 
B~
(Well of course, if you make a slip 2mmm thick you have to scrape it to death to make it playable, and therefore it becomes dull). I stand by my previous posts saying that a former below 70-72mm will cause a reed to be too thin, too ‘fluffy’ in tone, and prone to collapse. The staple design is of paramount importance if you use a shallow former.Too fat and the reed shuts, too flattened and the reed is too closed overall and causes tuning problems (amongst other things). When creating the scrape, note how the eye/lips open as you remove the bark. The wider the eye before scraping, the more adverse it’s reaction to the scrape. If the staple is formed with the correct gradient mandrill, the eye shouldn’t open too much, and then your work with the bridle is less about closing the reed as adjusting it’s playability. I think 1.3 - 1.5mm thick slip formed on a 78mm former is a good middle ground to start and go either side to your tastes. If it doesn’t work for you, check your staple!
And I do think, from experience of teaching reedmaking, that too thin a slip is the most common first mistake when first getting your teeth into, it. Oh and the other things too…endless…nameless…legion 
Alan