Felt & tri fitting experts,

I'm looking to pick up a Felt B12 or B14 in the next few days and am trying to determine the appropriate size. I never thought this would be such a painfully confusing process, but it's turned out that way, and here's why...

I've been to 2 of my LBS's: the first tells me I'd be best on a 54cm, the second a 56cm (this LBS perhaps not so coincidentally only happens to have a 56cm B14). So I sent an email to Felt with the below measurements. I didn't hear back for a few days so decided to give them a call - they recommended either a 56 or 58 based on my height. Then I get an email response from Felt recommending a 54...

Here are my measurements in inches:
Inseam: 34
Trunk: 25
Forearm: 13
Arm: 24.75
Thigh: 23
Lower Leg: 21.875
Sternal Notch: 58.5
Total Body Height: 70.625

So, naturally I take the 56 out on a test ride from LBS #2 and it's difficult to feel what's right considering the only adjustment made is seatpost height. I feel extended, particularly the shoulder angle between my back and my arms (probably about 110-120 degrees), but the shop says it'll be the perfect size once I buy the bike and they do a fitting. Yeah, it sounds like they're really pressing a sale, but who knows, maybe they actually know what they're talking about? I haven't been able to find a 54 to test ride.

Anyway, sorry to post a question that benefits only one rider in a forum of many, but I've been pulling my hair out a bit over this ordeal. Thanks in advance!