For a 2 inch lift we double the length of the shackles so i guess if you only want to raise it by 1 inch then the shackles only need to be one and a half times the standard length!
If you have a very early frontera it may be worth replacing the springs too as this will make some difference!
Cheers
Mark
ps, i used SMJ springs when i replaced mine but not sure they are still around!