mikesbytes wrote:I don't understand the arm angle advice. What the advantage or disadvantage in arm angle?
When below a critical Reynolds number, vertical cylinders are typically present greater drag (at lowish yaw angles) than those with an incline. However that flips around the other way as Reynolds number increases. Interestingly, the Reynolds number of an upper arm moving through air at cycling speeds is close to that critical tipping point, so it can go either way. Depends on size of arm and speed of air flow. Being more stretched is good at lower yaw, but can become a penalty at higher yaw angles.
You don't generally want too much angle either, as the upper arm then becomes a lever supporting your upper body and you end up requiring effort to maintain position, while elbows under ears means the upper body can be more relaxed, weight is borne straight down the upper arm bone. It's a balance of many things.
The top tube doesn't necessarily need to be higher, as that can be addressed with use of aero spacers under the elbow supports with the right sort of bars. It's often preferable to manage it that way, it's generally better from an aero POV, but if the bike is too short to start with, well that won't help. Think about the tall riders that have those bars with tall spacers under elbow supports. It reduces frontal area and also provides for better air flow.
First things first though, sort out the pedal/saddle relationship, then sort out the front end. One can rotate around the BB then to experiment with options, and depending on the regulations (UCI or Triathlon).