America is a large friendly dog in a very small room.  Every time it wags its tail, it knocks over a chair. - Arnold Toynbee (1889-1975)

If in the meantime you have the skills to do justice showing this breeders dogs (I assume you do since the breeder is asking you to do this), then take the dogs on just for expenses.  It's part of the learning process.  BTW, just make sure the breeder intends to pay your expenses.  I've known plenty who will just give you a dog to show, fully expecting you to pay for the expenses.  Nothing wrong with that as long as both parties understand how the show expenses are being handled.   And be realistic about your skills.  You want to be successful in your first endeavor showing for someone else.  It doesn't do much for you if you present the dog poorly.  If you don't have the skills yet for that breed, better to study first and then try showing.  In which case I'd only take on one dog to "play with" while learning.  You mentioned its a small breed that requires grooming.  Even some seemingly "simple" dogs to groom have way more that goes into grooming then one would guess. 

>What should be my daily base fee for the first dog? What should be my >hourly fee on show days for the first dog? The second dog?

It's not typical to charge an "hourly" fee.  Handling fees are charged by the class/show.  I have known a few handlers who do something different...such as I knew one who charged a rate per point.  But the others are paid by the class.  Proved to the owner that the handler was serious, knowledgeable, and helped her gain experience quickly.  For if she showed and lost, she didn't get paid.  If she did her job well (part of doing the job well means knowing how to select dogs who can win)...she'd be well paid.  I thought it was a creative way for a young handler to attract clients and not just take peoples money.  BTW, sometimes dogs such as those that are "specialed" are charged a flat monthly or yearly rate as well. 

I don't know how much things have changed in recent years.  But some handlers charge a flat rate board for the month.  Others charge "per day".   I think I was quoted $20 a day for board just last spring by a top professional.  I thought that was a little high, but I have nothing to compare it to.  Certainly boarding kennels are charging about that much, so it does make sense.   Expenses for travelling to the shows is split between the number of dogs a handler is carrying.  There is usuaully a flat fee and any "extras" are added on (such as showing in the breed, group, etc).  I believe current flat rates for experienced professionals range from $65-125.  Bonus's are often spelled out in the contract too.   Personally though, I disagree with charging a client to take the dog back in for winners or best of breed should it qualify.  And I find it terrible to spell out bonuses (for winning champion points, breed points, placing in group).  Bonus's should be whatever gift the owner wishes to give.  Still many handlers do charge "bonus's".   

And don't forget the issue of liability even if you just do this for the experience and expenses only.  What happens if the dog gets injured, ill, bites someone or a dog, or worse.