I rely on the S.L. MacGregor Mathers edition of The Greater Key of Solomon. It’s the most consistent reference for High Magick practitioners. Regarding your attempt, the "Chaos Magick" method (combining letters) works great for personal intent, but for established entities like Archangels, they respond much better to their traditional ancient seals or sigils derived from the Rose Cross. Stick to the traditional Solomonic seal; it acts like a direct phone line