I guess that would work. A lil plant like that won't do much absorbing...never tried it before when they're that small. If there's a lot of absorption it will be from wicking of the soil itself via evaporation and not from root pull.
Another option is to just keep it simple until they get a little bigger. You could water every day or every other day, just enough to wet the soil around the plant and down below the soil to about the above-soil height of the plant. It's intuitive - don't over think it.
Cannabis responds really well to drying out between waterings. You're more likely to overwater and over-feed than under-water and feed..In general the amount you need to water is going to be the minimum you can get away with using so that the soil is mostly dry before your next watering. The wetter you get, the longer it'll take to dry out...but don't water again until it's mostly dry. The use of water will depend on the size of the plant, the amount of light you're using (evaporation), and the amount of water retained by your soil.
I've always used things to cut down my soil mixes so that they drain better...perlite works well, a mix of perlite and light warrior with whatever soil you're using works very well. This allowed me consistent daily waterings with no risk of rot whatsoever and less risk for nute burn...it just doesn't retain all those salts as much and is easy to flush if needed. But, I am a hydro guy, so I'm biased towards removing soil
If you want, you could get away with making that change now before the roots expand significantly.
