(oops sorry I'm not a legend, and sure the SLDR as I've seen a few players above L96 and 98 STILL using the SLDR sometimes)
If I have any ball w/ a larger distance rating (over 2-ish) unless there is weird elevation/topography, I will use a little to moderate top spin. The exception is when there is some tailwind that will carry a driven ball w/ some BS (higher traj.) further than a extra distance ball w/ some TS.
The extra distance provided by the ball really shines w/ a little TS from my experience. If there is too much TS your drive may sink too fast. **
If there is a larger headwind, I've found and tested* the R1 and the BB drivers (see my posts on drivers and tests) and found that 1/2 to full TS is better than no spin at all. (generally, there are exceptions)
Sometimes driving to a lower elevation with a ball w/ high spin TS can make the roll out a very long distance.
With the Nike 85 irons I had great games w/ the Call. 34 and 37, also the Nike 42 and 61 ball may have some extra distance that might help, but I see the extra distance mostly on the drives not the shots with the irons.
The extra distance from a ball with 4 plus distance rating I get on the drive, mainly, with frontwind or very little tailwind (general FW conditions) I will add a little to 2/3 TS. Usually a ding shot will go farther, tests* suggest, under some conditions, that a 'hook' or pre-ding against a crosswind from left to right might cause a drive to go as long as a dinged shot or beyond. Whatever...
But if there is a larger tailwind, using 1/2 to FBS will cause a very long drive because the wind is pushing it as the traj. is now keeping it in the air longer.
Simply:
If using a ball w/ extra distance 3.5, 4, 4.5. 5 etc. using a little TS can help esp. in a frontwind.
In a tailwind put more BS depending on how strong the wind is. (BS can halt roll out sometimes, so the proper balance between the two is key)
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Individual results can vary, this is only my experience.
* http://www.wgt.com/forums/p/195080/1811460.aspx#1811460
Sandmancan11:
.For instance on hole 18 at merion if i have a 14 mph head wind cant make the fairway with a perfect ding with my 275 taylor made, need some helpful advise from some legends ! Thank you !
Merion #18 may be different from STA #1. Merion #18 FW topography & elevation may play a factor** in what is the best spin for distance...
... but this test on STA #1 into a frontwind suggests that, in this instance, a ball w/ full TS will go farther than a ball with full BS into this front wind (approx. from 11 to 5 o clock).
** But on Merion #18 if you need to pass the rough and get to the FW start, you have to use just the right amount of spin to get the ball to the FW so too much BS and the ball goes up instead of forward (esp. with a strong frontwind like you said) , too much TS and the ball sinks into the rough just before the start of the FW and never even gets to the roll out point at all.
Nice example, Sandmancan