Own two tarps. Both Spinn. MC Delux and WB Mamajamba. The MC & I have spent a few nights experiencing moderately high winds (+30mph) and driving rainstorms. Stayed dry. Have yet to use the BMJ under similar conditions. Picked it up for wet or colder season camping and the hopes of one day taking a trip to Molokai probably during the wet season. Previous trips to Maui we experienced rain almost every day. This was during April & into early May. Larger tarp for more dry living area more than for more dry sleeping room. If you have not yet considered the WB MJ take a look. The Spinn packs small for the size and is relatively light.
Curious about your work. Any published info regarding the bird survey? Many moons ago I was planning to either head to graduate school or what I ended up doing. Graduate studies would have been in population genetics/ornithology investigating migratory behavior & patterns of the Bald Eagle. Do you end up hauling water to most your base camps?