Here are a couple of answers. Keep in mind that these are just my opinions and that they are built on a couple of assumptions:
1. the PRSG shafts are right for you and that you have chosen them for some reason
2. that all the blanks are exactly the same in terms of weight and profile and that this model does not dictate that each shaft goes into a particular numbered head (I'm not familiar with these shafts and I can't find any information on them, so I can't verify this for myself).
- Should you weigh the shafts?
In a perfect world the answer would be no because all the shafts would weigh the same and so would all the heads. In that perfect world, when you built all the clubs to the same length they would have the same total weight and MOI. But in the real world, I would certainly weigh them. However, this would not be to put them in some kind of weight progression. Instead, I would weigh all of the components--shafts, heads, and grips--and match them to try achieving as close to equal total weights as possible.
(NOTE: IF all the heads and grips were exactly the same weights (which they're not going to be, but lets just say that for a larf), I would still weigh my shafts and then insert them in some kind of weight progression. For example, I would probably put my heaviest shaft in my short irons, but that's just me. Again, this won't be the case, so this is just a hypothetical.)
- Should you soft step?
Maybe. Personally, I'm not a big believer that soft/hard-stepping, particularly one step, makes that much difference. But if you do, then, hey, go crazy. I am quite a firm believer, however, that doing so will NOT affect ball flight in any way (directional or slice/hook tendency). The effect will be on feel and particularly the feel of impact. For example, a tip that is too stiff can feel harsh. I don't want to downplay this entirely, though, because feel can certainly affect the swing, which will affect ball flight.
If you want to play with soft-stepping, if I was in your shoes and had the supplies you have I would take the following approach (even though it is considerably more work):
- Do the the weight calculation and component matching as I described to achieve the most consistent total weight possible
- Choose a club that you are comfortable hitting: say, a 6- or 7-iron (I wouldn't go lower than that).
- Tip trim to a 6-iron length (3.0", according to your chart) and glue the head onto the shaft.
- Cut the shaft to about a 5-iron length. Why a 5-iron length? Because if you decide to do further tip trimming, you will want some extra shaft to accommodate this cut.
- Hit some balls using a split grip (i.e., a grip cut lengthwise with the butt cap cut off). When hitting balls, you are trying to determine two things: the length that is generating the most consistent hits close to centre (that may be a 7-iron, an 8-iron, or something in between); and seeing how the contact feels. If the contact feels muted or "soft," remove the head, tip trim some more, glue the head, and hit some more balls with the split grip.
- Once you are happy with tip trim and you have established the length you want to build to, cut the shaft and put on a grip (remember to cut the shaft 1/8" short to allow for the grip cap). This club becomes the model for all your other clubs.
(BTW, even if I wasn't going to fool around with soft-stepping I would still follow these steps. I would just do the tip trimming to "standard" and then use these steps to establish playing length.)
You could take this "model" a step further and hit balls with it, adding lead tape to find on-centre hits, and then use tip weights to mimic this club in the rest of your set. However, I would prefer to just build the other clubs to this unweighted model and use lead tape on each of my clubs to find the optimum weight with each of them. I would finish off by having my lies and lofts done.
A Final Note on Tipping and Soft-Stepping
IMPORTANT: Remember that you are going to tip ALL of the shafts the exact same amount. There is not progression to the tipping like there is in a variable length set. So, if you chose to build these to a 7-iron length and you wanted to soft-step these, ALL of the irons will be tipped 3.0".
(QUESTION FOR OTHER BUILDERS: If the Pinhawks are weighted to be built at an 8-iron length, and the builder builds them at a 7-iron length with a 7-iron tipping, aren't the clubs already soft-stepped once? WestSideBengal, you may want to take this head weight thing into consideration when deciding on how to tip.)