Stunted growth

probably won't get much larger... it'll ripen.. calyxes will plump up but the 'vege' growth is/was done for a while. there is variety in rate of ripening... you can guess but it comes down to observing and reacting... guessing doesn't help.. it'll just influence your choice. The calyxes are far from 'plump' you are weeks away. did you defoliate? that likely had more of an effect than pH. medium needs moer aeration (perlite or similar) and watering habits look odd based on drying pattern, which could be part of the pH issue you say exists. 1 - fully saturate - this should never cause a problem and if it does it is the result of a poorly constituted soil. 2 - wait for appropriate dryback - this has some leeway as to the exact point you do it, but som minimal dryback/loss of weight is necessary to avoid overwatering. you give the volume that is required to accomplish the tast, and you react to a certain loss of weight or depth of dry medium on top and repeat. Neither is a top-down choice. You don't choose the volume nor the increment of time. Watering is merely a reaction to observations. All of this stuff can contribute to a slower growing plant, which with an autoflower means a smaller flowering plant.