The only reason to go a quarter at a time is that it can have a large effect. Watch videos of REAL luthiers working on neglected instruments and they crank away on rods, a full turn or more. Of course their experience allows them to judge approx , just by looking, how much an instrument needs to get it in shape. Your bass is probably close so you won't have to get whacky with the Allen wrench. Settling kind of makes me laugh: that's a steel rod, am I supposed to wait for it to stretch? For the wood at the anchor points to squish?
'73-4 Ampeg V4B, Ampeg PF350,PF115HE, PF115LF, 115 Traynor, 1962 Fender Jazz, 75 Gibson G3, '10 Squier VM Jazz, Squier CV 60's P Sonic, Squier CV 50's P blonde, Epiphone Thunderbird IV