Is that 6 fluid ounces or 6 ounces dry measure?. The measure is slightly different but I don't think that will make any difference in soap making. 1 ounce (mass) = 28.35 grams; therefore, 6 ounces = 170 grams and 8 oz = 227 grams.
I should point out that if you are making it with wood ash, you will be using KOH and not NaOH.
moles NaOH = 58/40 = 1.45.
Assuming that adding NaOH to 170 mL water doesn't change the volume of the water (not exactly a good assumption), then
M NaOH = 1.45/0.170 = 8.5 M OH^- which gives you a crazy number like -0.93 for pOH and 14.93 for pH (remember the scale only goes to 14). None of that really makes sense anyway because in a concd solution such as that the pH doesn't mean very much. Remember, too, that if you are using wood ash for the KOH, that will not be pure KOH. Technically, it is K2O (and only a small percentage at that) in the wood ash and becomes KOH when dissolved in water.
87/40 = 2.17 moles and
2.17/0.170 = 12.8M for OH^- and the pH =15.1.
If you want to recalculate for KOH, use 56 for the molar mass KOH instead of 40 for NaOH.
Follow the above for the 8 oz (227 grams). The numbers won't be that different.