With the inclusion of horde units in 8th edition, there is a push to field a 10 wide horde unit. I do not like this idea myself. I prefer a unit that is 7 or 8 wide at most. I play Lizardmen primarily and I can fit 3 Kroxigors in the second rank behind 8 skinks. I have tried running a 10 wide unit of 30 and did not like it. It was too hard to move that unit and they never had frontage on another unit that size. It makes more since to keep it at 7 or so (to me). The unit remains stubborn anyway (due to outnumbering your opponent). Another note is that you can always reform the line to increase or decrease your frontage. If you win combat resolution, it is a free reform and if you lose, you must make a Ld check at your modified Ld from the combat resolution.