might need it open a tad more I have one that needs 2-3 mm gap the 1mm is just a starting point
also make sure the servo isn't pushing it closed past 1mm I had one do that before as its idle point was set too far back

as for tools I just use a allen key set, a cheap $9 screwdriver with multiple heads that store in the handle, a pair of pliers I got for $1, a Duratrax ultimate car wrench, and my dremel
pretty much outside the alen key set, and Duratrax car wrench I had everything else for many years