I second this, I've been trying to figure out if a certain distribution of stats on the tribute card has an effect on the stat increase of the other card, but I have not really found anything. I have this feeling that a card with a stat of 1 atk will not add attack to the other card, same for HP and Def, but thats all I have and its not even confirmed.
Same goes for the glyphs, I have no clue what berry it would increase in cost and that would actually be really useful.