Try using the top 2 or 3 leaves from the 84-89 rears with the bottom 3 leaves of a stock solid axle Toyota front pack.  Then of course add or subtract to taste.  I used this on my stock-ish '80 pickup to use rears up front for a 1.5" to  2" lift, they are nearly flat and act like front springs with the extra overload type leaf material mostly to the back of the pack.  It worked so well on the '80 I mimicked the same setup on my RUF 4Runner when I was trying to lower it.  I got increased spring rate and I was able to lower the whole setup a good 2" or so plus it rides better than using all rear leaves.  The springs on my 4Runner's RUF were emus from a 94 pickup.

Here is the RUF with '84-'89 4Runner rears for the top 3 leaves and the bottom 3 from a stock '80s front pack.  You can see they are pretty flat and low... The second pic down is the springs on my 4Runner whch are the '94 emu rears for the top 3 and the rest of the leaves are from a stock 1st gen front pack. This whole setup is taller but the springs have only minimal arch and handle and ride well, not to mention both setups flex great.