Have a 3" leveling kit - Can I add a 3" lift Spindle and add a leaf to get ~6"

I know this has probably been asked - so references to past threads appreciated.

I have a 2016 Tundra 2WD CM that I put a 3" leveling kit on a few years back - but
want to raise it to around 6" (2wd truck... all 4 looks).

I am looking at adding a 3" lift spindle and longer shackles or an add a leaf in the rear
to increase rear height on top of the 2" block I added with the leveling kit.

I am running 20" x 9" wheels (Gear Big Blocks) with +18 offset so think I have clearance
for the spindles.

I see 6" spindle kits that use the strut spacer - so think my plan for the front will
work. I am trying to keep the cost reasonable here without compromising safety
and excessive wear on suspension.

Is this plan a reasonable approach for a 2WD model - or totally a hack and I should
go a different route. This site rocks - so would love any input from those who have
been down this road. Thanks !