In terms of econ heavy vs accounting, you can look at the required courses in the major here: https://my.sa.ucsb.edu/catalog/Current/Documents/2015_Majors/LS/Econ/Econ-Accounting-BA-2015.pdf
The description of each course listed is here: http://www.econ.ucsb.edu/undergraduate/courses.html
After briefly looking through, it seems like there are a fair amount of accounting courses in the major so it’s not entirely dominated by Econ. All I can gather through my friends who went there in that major is that Econ10A is definitely intense (some of them have already changed majors after taking that course). I would definitely reconsider how you feel about Economics and see if you can decide if it’s something you like or don’t like. That’s all I can answer for you, good luck!