Shadow - A thumb screw would be recommended, but it depends on your particular circumstance. If you plan on agressively swinging the blade around or dueling with it / hitting it against objects, then I would recommend a thumb screw. If the blade is a VERY tight fit in your blade holder AND you are not dueling with it, just using it for show and light play ... then you may not need one.
In the 3-piece blade board set up you may see 2 areas on the blade that appear to not be as bright as the rest of the blade (this greatly depends on how the blade was put together). This is because each board is connected to the next board with wires ... however with the V2 blades Jim has been able to greatly minimize this problem. And, if you choose the 1-piece blade board it is improved even further.
Alias - I appologize but I am confused by what you said. Maybe you are referring to something other than the Hyperblade and that's why I am not understanding. If an LED were to "pop" or go out on the Hyperblade it would be VERY noticable. The LEDs on the blade are not next to each other. They are on the board 1 at a time all the way to the top. If one were to go out it would be extremely obvious. As of yet, out of everyone I have met or sopken to that has a hyperblade no one has ever broken an LED due to dueling. I myself have dueled with mine and had no problem. And I have seen a Hyperblade destroy an MR saber and show no signs of problems. I have seen a "short" occur that caused a series of LEDs to go out and that is usually simple for Jim to fix. Now, I happen to agree with you ... I do not usually duel with my Hyperblade and I prefer not to ... but so far it has proven itself to be duel worthy.