Originally Posted by cyclezen

'Fitting' on the internet - Bike Forums - is an iffy thing - too much to consider and too little real info...
In consideration of bike types and models...
The Trek Alpha is a 'Hybrid', intended to be ridden more upright, city type, short reach to upright straight bars...
Trek Madone is a performance/race bike, intended for forward/lower lean to torso, so geometry of the bike will be quite different.
The Synapse is in-between, but more oriented towards the 'performance' side of riding.
Based on info you give, and saying the Madone 60 felt 'good', I would say the 58 Synapse would be closer to the Madone 60. and still be a bit more upright than the Madone...
If you'd like a closer comparison to the Synapse, and want something a TREK dealer has, try the Domane. I think you'll find it closer to how the Synapse will 'fit'.
Agian, based on your limited info, long legs/arms, 6'1", I would lean towards the 58 Synapse...
Ride On
Yuri