5 lt is about $70 in SA.
I think you can mix them all, but some you need to agitate more and keep mixing as after 24 hrs they seperate out in odd ratios.
umm i still have a 20 lt drum of castor in NZ zealand you can buy of TM bill.
Maxima also do a PRe mix castor oil, it comes in a black bottle purple label and runs in like normal 2 smoke oil. I used that in my 2 smoker i put on meth