I was fortunate enough to have a good friend over to work on a new blend from 5 great coffees.  I always sample roast to peak body (fully swelled beans before second crack) and then cup as espresso to determine the character of the coffee on its own. From there, I build a blend, where there is always give and take. Unfortunately, bean density matters and it can be difficult to capture the nuances of each component when they don't grind the same for espresso. At the end of the session, we loved the heavy body and chocolate tones of the Guatemala and felt they would best wrap around the fruit-bomb Guji. Both are very high altitude (1400-1800m) and work beautifully together.