If it turns out to be crazy thick, you may want to thin it out then. If its too thick, you will get problems with lodging (falling over). If 25 is good, 50 is not better. I'm sure you will be fine. I'm glad too! I'll see if I can find a typical looking square foot and get a count. I also read that high fertility can cause lodging so I didn't amend the soil like I would for a veggie garden, just a small amount of organic fertilizer.
I'm just happy I can put that Masters degree in seed technology to use finally
High fertility, particularly high N can cause lodging in most grass crops. High nitrogen promotes cell growth and elongation and you end up with a taller than ideal plant that can't support the weight of its own grain.
In malting barley, you don't want overly high N anyway because the higher the available N, the higher the grain protein. You need adequate N to get proper yield but if you have too much then you get too much protein. Your approach to use a compost is likely best since you don't have soil tests (I assume) to properly balance your nutrients. If you do use a fertilizer, something low and balanced would be best (10-10-10 or lower for example).