Hydration

Dave, I am no expert, but it does not matter if your hydration is 95% or 100% . If it is a big difference, say 75% v. 100%, yes it can matter.  I find that the wetter the starter, the quicker it develops,  so if you made a 75% starter and a 100% starter, and let each one sit out the same amount of time, the 100% starter may have already peaked and started to recede while the 75% starter may still be rising.  I also understand that hydration level can impact the sourness of the starter - and while I have read contradictory info, my understanding is that all other things being equal, a more liquid starter will be more sour than a drier starter.   Finally,  I agree with everyone else, get a scale, preferably electronic, they can be found for under $20 at a number of places.  As an aside, one thing I can't understand is when recipes say to use 1 cup of starter -  as we know, the volume of a starter is always changing, increasing at first and decreasing later, and the mere attempt to measure it will lose some volume.  So how 1 cup of starter would have any set meaning is a mystery to me.  On the other hand,  100 grams of starter will always be 100 grams, whether if fills 1/2 cup,  1 cup or 1 1/2 cup depending on how much it has increased in volume since its last feeding.