Glade that this thread is a bit more civil. I apologize for getting frustrated with the other thread but it seemed as though bits and pieces of information kept surfacing and the story was not what it appeared to be.
Having said that, I am very glad to hear that your gf is willing to shoulder some of the training responsibilities. It does take effort on all those involved to work together for a common goal. You said that she has a roommate, is there anyway that that person could come home in the middle of the day and take Ollie out for a walk? If this is not an option, seriously consider using an expen. In my opionion, it is a better option because this gives them stretching room. I wouldn't want to be confined in a cubicle for hours at a time.
As for the treats, I would give one each time he potty's. If you are concerned with the type of treats, we have been giving pieces of carrots. They go nuts when they hear the crunch of them. I use the baby carrots and will eat one or two-good for me as well.
I also give Zuke's but I break them in half and each get one.
Lil fu fu girl has a great idea for a command for pottying. We use "do your stuff". I have read that you should say it when they are actually in the act so they can associate it with the act and learn it accordingly. Again, whatever you decide, both of you need to use the same command.
I, as the others have, would like to Thank You for your sacrifices in keeping our country safe. My brother and husband are vets from the "conflict" and I say Thank You to them every veteren's day. Stay safe.
Here is a picture of the expen that we use; you can put a clear shower liner underneath it to make easier for cleanups: