Whatever you do, if your runways are less than 2500 metres, do NOT get suckered in to the wing/flap modification that is marketed for this old beast.
Although it is not particularly expensive, it totally ruins a good airframe.
It was created specifically for a very long runway/high elevation situation - like Mexico City - to overcome climb limitations. It works best at Flap 1 or 2 and I think it offers an intermediate setting at about 7 for situations where 5 or 10 is not optimum (but I have forgotten the details of this).
On runways less than about 2000 metres it is more likely that accelerate-stop will be the performance driver. Between 2000 and 2500 metres optimum take-off weight usually becomes a juggling act between field limits and climb limits.
The modified wing won't help here, as V1 for any given weight/flap is much the same with or without the modifications. Distance to reach V1 is basically a function of thrust versus weight and for a given weight that distance wouldn't vary much even with NO wings! The modified wing/flap may marginally improve acceleration (by getting the weight off the wheels a bit sooner), but it would be so marginal that it would not be worth the expense. Bigger engines - like dash 17s - are the only cure.
The AFM will give you all the info you need to manually calculate speeds etc, but one of the after-market performance providers will do it quicker and probably more accurately. At a cost, but what is your time worth?
Also they have all the survey data, so when the Feds come calling to ask how you derive your numbers, it is easier to pass the buck. I certainly would not be making up my own speed cards by the pidooma method.