Mesquite vs Oak for my porter?

I have a roasty porter that I'm transferring to the secondary tomorrow and i just had the idea to add wood chips while in the secondary. This will be my first time experimenting with wood chips. I'm pretty sure all i can find at the grocery store would be mesquite or oak grilling chips.

My question is, which would you recommend? What are the flavor differences? How much should i use? And any other tips you have would be greatly appreciated.

Thanks

Ok i just found a post saying not to use mesquite. So thats out. But I forgot about hickory. Im sure i could find that. Any comments?

Go to De Falcos and get some Oak Toasted. You will be much happier.