Ive started off using a seedling mix that was 90% buffered coco and eventually found success with both coco only and 50/50 coco/potting soil mixture. I learnt the hard way that its best to buy premium potting soils since the cheap stuff usually contains too many bugs in the soil mixture leaving you with fungis knats. The same for compost. I personally think your soil mixture contains way too high a proportion of worm castings. Potting soils will mostly contain a compost pre mixed in and if you combine this with your worm casting the soil may be too nutrient rich. I would go 2 parts coco,2 parts potting soil with 1 part worm castings and 1 part perlite. I would use less perlite if the temperatures are a bit hot since the soil tends to dry out faster with more perlite. Do not use this mixture for germination. Keep in mind that germinating seeds and seedlings can die from too much fertilizer or no fertilizer at all (if they have developed their first set of real leaves). A 50/50 coco potting soil mix seems to dilute the potting soil enough so that it has just enough to get a plant going and feed it through weeks 1 and 2. I prefer this because the plant gets used to the soil early and won't shock if moved from pure coco to soil/coco mix when transplanting. When the time comes to consider adding fertilizer I think it would be good to consider seagro fish emulsion and molasses. Seagro will not give your plants fertilizer burn and is mostly safe.
I saw someone mention freedom farms soil above , and I personally love their soil however I find its too expensive and the same results can be achieved using good but cheaper premium potting soil and coco. I think you will find the mixture i mention above will result in a soil that feels and looks as good as what you would buy from freedom farms. Once you get your hands into both soils and feel them a bit you will notice the same airy fluffy, light texture in both.