Constructed languages have a history of failing when one person tries to keep control over them. Volapuk was an invented international language that was very very complicated, but still was quite popular for a time, until some of its proponents decided it should be simplified. Its inventor refused... and Volapuk sank into oblivion, remaining only in the Esperanto idiom "g^i estas volapukag^o" which translates as "It's Greek to me." Calvin Mooers, back around 1980, invented a macro processor called "Trac" that was quite useful, but kept such strict control over his intellectual property that Trac is now forgotten.
The SignWriting web site has a few introductory lessons... but to learn to seriously use it, you get to buy some pretty expensive instructional material. Any kind of writing system for ASL is going to have to be public domain or "Open Source" to be widely adopted.
Also, pictographic symbols don't lend themselves to fast writing.
How do you plan to represent borrowed terms that are fingerspelled?
Whatever system you come up with should be something that can be written fluently, and ideally it should have a convenient form for entry online. I'm not sure how to pull that off for signed languages, which take advantage of the multidimensional signing space... but I certainly hope you do. My interest is partly selfish. If I want to learn a spoken language with a written form, with few exceptions I have vast corpuses of grammatical utterances that I can study at my leisure, letting me not have to do two things at once in real time right away (break down continuous speech into words and figure out how they make up phrases and sentences). I'd like the same capability when I try to learn ASL.
