Cycling induced anoesis
Gotta break with you on this one, Platy. Just because you're willing to live with the requisite compromises that come with varying frame size by up to 4cm 's (1/2 that being huge in terms of bike fit) doesn't make it good advice for others to follow.It's amazing that anyone ever had a bike that fit them, if you believe all of the marketing BS about fitting. Here's a secret from a bike shop owner: bike fittings are a money-making load of crap created to make people think they need to spend money to get the right size of bike.
I'm 5'11" with a 29" inseam. I can ride a 52cm with a longer stem with no problem. I can ride a 54cm with no problem. I can ride a 56cm with no problem. Think about it... if you're in between a 54 and a 56, that's 2 cm. Take a look at how much 2 cm really is. Is that difference going to *really* be noticeable? Replace the 100mm stem with a 110mm and you've gained 10mm of that back without effecting the handling of the bike.
Believe me... general fit guides are usually good enough.
I know from experience it would never work for me, because stem length adjustments alone don't fully correct for rider position/ front/ rear weight distribution, and that (IMO/E) is the single most important aspect to fit and handling. I've ridden bikes one size off (2cm's) and they never felt quite right.
I wouldn't suggest the OP (or noobs in general) opt for a pro fitting from the get-go, but (assuming a reputable shop/ fitter), the results of a standard LBS fitting are far better than someone sizing from a chart and fitting themselves.
OP: You're right to be concerned with fit, but I've previously posted options you could employ to better your odds of getting sizing (then fitting) right with the DB. Once you get to Baltimore, shop around and be upfront with the LBS's about your situation and budget. You might find a shop willing to work with you on this, especially if they see you as a prospective customer, albeit for the short term.