My mojo frame will be here soon and I'll be trailing some seatposts. As I don't have any suitable posts I'm going to get a cheap one for testing. I'm exaclty 6' and will have a large frame.
Should I start with a zero set back or get a ~2.5cm setback. I will also be trying different size stems (which I do have) 100 vs 110.
Depends on your riding preferences. And your fit.
For normal proportioned riders on the 73 degree seat tube angle Mojo, 0 setback is best for climbing and efficiency pedaling long distance. And a set back seat position is easier to wheelie and aids rough technical for manualling up obstacle step-ups but climbing and pedaling is less efficient.
Also set back seats are used for XC riders with extra long upper leg bone length to keep to seat height low. A long stem, 120mm or even more, and low bars would be used to keep rider weight balanced over the pedals for climbing. But technical handling is compromised with long stems.
It's the axle
I was just doing a search on this yesterday. If I recall, this might have been the thread with some good info.
fore/aft saddle position
I know where I'm comfortable on my bike. And it doesn't seem to correspond to the standard seating position.
To be honest, I think it's a dynamic thing. And it's definitely a riding preference.
I've a zero offset, and my seat is all the way forward. But then, I'm a climber. 135 pounds. After trying the knee over pedal axle measurement, I realized that I've made the decision as to where my seat should be according to how I feel.
I have a suggestion. Try different positions. Push the seat way back, and see how you ride. Then go the other way.
I think you're smart to start off with a demo post, and just see. I guess in a word, experimentation will yield your answer.
Now, where do I ride today? Hmm, decisions...