Bamboo and Exotic Wood Floors - sealing bamboo flooring?

I just bought 800 sq ft of Home Legend PreFinished bamboo floors from home depot. They are solid Bamboo and they are beautiful and all seem to be very straight and an overall good product. My only concern is I have 4 kids and two dogs and a busy house and I noticed from opening just one package and laying down just to get a feel for what it was going to look like in my house that the planks I pulled out already have scratches on them just from me taking them out for a short period of time! The finish on them is very thin. Does anyone know if it would be safe for me to put some sort of polyurethane sealant over the floor once I have it installed? I am worried that if I do and I don't get the RIGHT kind of sealant that it will warp the boards. Is anyone familiar with sealing bamboo flooring? Particularly this brand? Also I have another question! The area we are putting it in is an L shaped area. This area has 4 windows plus a sliding glass door width wise and only 1 window lengthwise. I know that it is recommended that you install wood floors lengthwise with a room, but the directions say they generally "should be installed lengthwise to the main incoming light source" and then goes to say "WHERE POSSIBLE down the length of the room". So my husband and I are arguing about this because not only do I feel installing them width wise will make the area appear wider but all the incoming light sources are in that direction, but my husband INSISTS we are installing them lengthwise and refuses to listen to me. And with an L shaped room, there are two "length of room" possibilities if you think about it. Does anyone know the exact reason they say to install them lengthwise towards the main incoming light source? Is it an important reason i can tell my husband so he will listen to me?? Thank you everyone in advance!