3IU's is the perfect starting dosage. You should definitely notice some improved sleep on that if you take it pre bed. You may also notice some muscle fullness but it all depends on diet, body fat percentage etc. Recovery should start to improve as well. It can take months for HGH to truly shine which is why I always suggest running it long term.
I wouldn't consider 225mg of tren a small dose haha. I'd consider that a moderate dose as a little bit of tren goes a long ways. As long as diet and training are dialed in you should have a great runt though! The synergistic effect of the hgh + tren + test should be a great combination
Keep us posted and let me know if I can ever be of any assistance to you