RE: OS SPEED .21 V-SPEC engine
It's not needle settings that affect the most when it comes to runtimes...fuel and tuned pipe will give you up to 4-5mins difference on the v-spec.
Needle settings more or less are around the same if the engines are tuned right according to weather conditions.
The weather affects those settings but it won't alter the runtimes more than 1 minute or so.