Rawsco is our male terrier pup that has been home with us just over 3 days.  He is feisty.  Of the 3 pups to choose from he was definately larger and more active than his 2 other brother's.

I have gone from board, to forum, to site, to calling obedience trainers and I'm getting the "whole she-bang".  

The problem is a small pyramid of problems that I am trying to balance and weigh.  Rawsco is teething, and I have tried to discipline him from biting my hands, fingers, clothing and from jumping up at/on me.

Things that I have tried:

Firmly closing his mouth and telling him "No."  Results in further aggression, rougher play and more biting.

Rolling him on his side until he calms down.  He wriggles, squirms, tries to bite (and when I say bite, it's more of a playful bite, none have ever drawn blood), and I continue, steadfast, but he will not relinquish his squirming and after a minute or so I fear for his safety, release and it results in further aggression, rougher play and more biting.

 
Things I have not tried:

Bitter Apple Spray - My GF feels that it may be risky to his psyche should we spray our hands.  She doesn't want to have the possibility that Rawsco mistakes this as he isn't allowed to interact with the human hand.

 
Things that seem to work. 

 
I have a plastic box that is just slightly smaller than his crate with holes in them that I place him in for "timeout".  I haven't perfected the method as I've read you should leave them in no longer than 10 seconds up to 15 minutes on various sites.

 
Questions

1.  What are some pro's and con's of using the Bitter Apple Spray?

2.  What is a good duration for the timeout enforcement so that I can be consistent?

3.  How serious could this escalate, temperment wise with Rawsco if I give him "a month or so" to "be a puppy?"

4.  *The vet has advised me to not allow him on the grass or places where other dogs may possibly carry diseases that he has yet not been vaccinated for.

How can I relieve his energy when he doesn't understand how to play yet? 

He has 4 toys.  A green plushie sort of toy that came with him.  A rubber grooved ball similar to the Kong sticks (w/ PB).  He has a red bone (which I am now trying to freeze to see if it'll get more action) and a ring (bigger than his head, not a safety threat, just not something I can describe very well).  Each time discipline was given, his toys were presented to him following punishment.  He just isn't very interested in them.  We do praise vocally and physically when he does interact with a toy, although he rarely does.

I appreciate your time for reading my post.