any speculation on what these might be.
wth I just checked some of the current prices and current values don't make sense.
Compare just Olthoi North, to Colosseum:
Tome = 10 at both...suggests a 1:1 ratio
upgrade kit = 10 at Olthoi, = 5 at colo...suggests a 2:1 ratio
salvaged pyreal = 12 at Olthoi, = 6 at colo...again suggests 2:1
MFK item = 10 at olthoi, 5 at colo...again 2:1
tunic = 10 at Olthoi, = 25 at Colo...suggests 2:5 ratio?
So I suppose if you only compare the exactly equivalent items, then you'll need 2 venom sacs to 1 colo coin. That is if there is no penalty for exchange rate. That already seems backwards, since you can get colo coins much faster than sacs. Although you can solo sacs easier.