Raising pH of water in fine but now though. pH of 6.4 does not slow down the establishement of bio activities. And also , at pH of 6.4, pretty much majority of ammonia is in non-toxic form, NH4+, ammonium ion. Thus I dont think you have to do pwc on daily basis. Just to keep it controllable/reasonable level so you wont have to deal with High NO2 peak as tank cycles.
Remember you need to have ammonia in water to establish bio activities (bacteria) and amt of of bioactivities will equal amt of bioload (ammonia), so dont go out of your way trying to keep it at .25ppm. Too much water changes can also delay cycling process.
The reason for not to mess with pH at this moment is a fact that as pH rise, NH4+ will shift to become toxic ammonia (NH3).
When tank is cycled and you wished to mess with pH, I would recommend to do so via water changes rather than adding chemical and/or other induced methods directly in/on the tank.
You can simply prepare and/or alter NEW WATER, vias whatever methods you choose (CC or baking soda),, before starting water changes. Thus when new water is added, it would be somewhat gradual changes.
I agree with others as to leaving the filters alone while cycling no matter how filthy filters may seem. I would not even vacuum unncessarily while cycling as bioactivities will take place on any surface areas in the tank.
Hope this helped a bit.