You don't need specific starting number. Just pick up a pot, bro. Has nothing to do with being dumb or not. The soil you are using is fine, but is much better with 20-25% perlite added to it, you can make that change next time.
Next time you water and fully saturate your media, pick up your pot like an inch or two off the floor and feel how heavy it is...if you have an empty pot, you can fill it with soil and this will give you an idea of how light it should feel when it is time to water again.
If you do not have an extra pot to fill, you can keep picking up your pot over the course of a few days and feel for yourself how the weight changes. It is very obvious. Also observe your plant.....the leaves will start to droop but more importantly the stems of those leaves will start to droop....when you see this, pick up your pot and feel how light it is. Now it is time to water - fully saturate your media and the process starts over - going forward, try to catch it before the stems drop....you'll pick it up in a few waterings and it will be simple.