1/4" Staples are best, assuring that the "Bar" of the staple sinks as firmly and as deep into the Velvet as possible, and thereby minimizing the amount of Tapping needed on Staple heads that still protrude above surface of the Velvet.
Generally speaking, I still take a hammer and tap a little bit on everything, with special attention to any point where I have two layers of velvet overlapping each other.
Posting the SyFabric Link is Ok. After all, they use Velvet for making Clothing, Drapes and Curtains. Now if they advertised it as being especially made for Wrapping Trim for Projector Screens, that would be different, and much the same as if someone posted a link for where to pick up the bulk Screen material that a DaLite or Stewart Screen uses.
Why, that almost happened with the 4'x8' + 5' x 10' Sheets of Parkland Polywall because after the info got out on AVS about the stuff, the rush for it caused the Mfg. to jack up the price and actually advertise it in the Parkland Plastics Site as being a "Front Projection Screen". (...the "Jack up" in price caused a backlash of unpopularity and as a result, Parkland dropped the panel altogether.)
It still rankles the nerves that they did that......
It's a fine line at times that separates some products from being "Over the Line", but one that is easy to balance on if one simply remembers that the rules "effectively" state;This DIY Forum is intended to provide help and advice toward the making of DIY Projection Screens using materials not originally designed and/or intended for use as components for such "Screens".
As for everything else, it's fortunate that it was determined awhile back that to exclude the posting of Links to available and applicable materials on a DIY Forum would be tantamount to shutting down the effectiveness of such a Forum to help others find such things and progress accordingly. The temptation always exists to fudge a bit, and anybody who wants to fudge for his Screen building convenience should be able to do so. By simply remembering that a "Screens Forum" exists and that such actual "Specially intended for Screens" products are highlighted on that Forum, there is and always will remain an outlet/source for such things for the "less than adroit" DIY'er who wants to make one or more aspects of his "DIY" project be a little easier and provide more assurance of success than he might be able to provide himself.
In such cases, saving money is not as important as getting the results one hopes for.
True DIY is all about getting the absolute MOST "Bang for the LEAST Buck", and then pointing at your work and saying "See how great it is....and it didn't cost much at all!"