I have only done this a few times, but has worked for me. I have never poked holes in the bottom of my containers. Just keep your eye on the seeds to make sure they aren't growing mold. You should microwave your soil also. Funny you posted this I just planted two different Notocactus' the other day. This is the first time I didn't use bags so we will see. If you have anymore questions feel free to ask :)

A few of the seeds I intend to plant over the next little while arrived today! Where I work we have tons of little containers so I planted my seeds in those and have them in a sealed plastic baggy. Before planting I microwaved the soil like I've heard and hopefully they grow!

Looks good you should have little babies in a bit. They usually don't sprout fast like a string bean so don't get discouraged:)

I use the baggy method, and like to have holes in the bottom of the pots, as it makes watering easier once they are out of the bag. It shouldn't make any difference at this stage, so I wouldn't disturb them. It should be easy to poke some holes in the bottoms of those containers in a few months when they come out.

Will they get direct sun through that window? If so, the greenhouse effect will make the bags too hot. Indirect sun only, for now. Good luck!

They shouldn't get any more then an hour of direct sun if any but if the weather here clears up I'll move them!