Did you get my PM (check your notifications), the little document I have covers most of that.
The purple barnacles are usually found at sea side junk shops and often on eBay.
I use a turkey baster but many people prefer the drip method (a cup is too fast). Acclimation is generally about 3 hours.
Here is a thread on trying to determine a male from his specialized arm. One of the photos is of a pair of mercs.
O.mercatoris will not acclimate to daylight. On occassion, Greg saw his out in shadow but the only time I have seen them out during daylight is just before the end. My females have been mostly inactive all the time.