>>177772210/10 people will say your pic is correct, but they'll never say "why".
What you suggest is reasonable, given that
A) toolless adjustment adds zero value (this is not something that you would adjust mid-ride)
B) unless you fucking jam that acorn nut on there (or loctite), you can only tighten the screw (trying to loosen it will unsrcew the acorn)
HOWEVER there are two reasons why they are installed phillips-in
A) 70 years ago, some Italian faggot drew it this way, and no one questioned it (Campagnolo used to be cool, btw)
B) when the screw bends ("when" not "if"), you have to cut off the bent part... when you do that, the same "acorn unscrews itself" issue means you want the phillips head on the not-bent side
Do yourself a favor, take them out & slam the wheel all the way back. Benefits include
A) More surface for your quick release/nut to bite into
B) Cassette moves further from your derailer, slightly increasing chain-cog contact, slightly increasing cog & chain life (look up Sheldon page on "chain wear")
C) You won't be here in two weeks asking "How 2 remove bent screw?"
