Leaf Springs

Im not sure I would lower the front, yet if at all.
Your car weighs a lot more than his and the power levels are different.
Set it to stock ride height for now, and yes...for now you should leave the springs and base line test it with the ride height right, the shackle plate blocks and correct pinion angle...and the new shocks you have.
after that, if the rear isn't moving enough 'raising', you could try the other weaker springs.
JMO