Since no one else has commented... The Lee Valley seed starting kit that I have has an open hole at the bottom where the soiless mix contacts the mat. I think that cell packs would not allow for enough soil contact unless the bottom is cut open.

I have used an old polyester blanket cut to size for capillary mats with no problems.

You will have to transplant the blocks into larger containers or blocks now. The longer you wait to do it the more damage that will be done. Transplanting prior to true leaf developments is done all the time by experienced growers. Waiting for true leaves is just a guideline used for those new to growing from seed. Dave

That is a chronic problem with capillary matting - it gets and stays too wet. The only solution I have found, only way to adjust it, is to reduce the size of the pot holes so they don't absorb so much water from it. That is how those automatic watering set ups work - small holes. Or transplanting the plants into much bigger pots so they don't get so soaked. In the past I tried wringing it out well, running it through the washer and dryer, cutting it into smaller strips so there was just a small strip right under the pots rather than a whole sheet of it (that helped some), and cutting the part that sits in the water down to a narrow strip so it can take up water more slowly (that helps a bit too). Either way it isn't ideal and I have lost whole trays of seedlings to it in the past so finally pitched it. Sorry I can't be of more help. Dave