Been doing this for years scraping touch ups, top crack splints, etc. I use "old style" razor blades and tape the edges on both sides at the same time. Some put a burr on the edge, like you do on scrapers, but I feel that these cheap thin Indian made razor blades have that burr already: you can always find which side scrapes better :)
Pre bending a blade? Cool...
I've always like grinding-off the corners before taping, just to help reduce the risk of "tilt n' scratch". A few bad experiences proved to be a mighty good teacher :)
Interesting idea there to pre-bend the blade... I usually just flex it by hand while scraping to get a feel for the amount of curve, but you might be on to something there.
Tensioning the curve is one less force I have to deal with while scraping , and I can adjust the depth of cut by angling the blade more or less, rather than deal with how much curve I'm applying to the blade. There's a constant arc that's adjusted by blade angle ;) I find it's easier..
I guess I've done this the other way around. I used to bend my into a curve after taping the ends but I stopped because I feel like I have better control if I flex it as needed. In fact, I've found that I don't need the tape nearly as much because since the flex lifts the corners. My bench is littered with razor blades