i agree with james, i've set bikes up to what im used to before, and ruined them just because it initially felt comfortable and 'normal'. I reckon now to try and treat each bike as a tool for its specific purpose, so my old xc bike is super long 90s geo. street bike is fairly short and really high, stock is as low and as long as i can get the front end and the new enduro bike is mid to long reach with a titchy stem. switching bikes only feels odd for a few seconds, and then just feels like home.