Scrub radius does not mean yer a newb

Ok. Just learning about scrub radius here.
Aparently it's not a name for someone new to rig building.
I hae a stock 2000 taco, v6 XtraCab.
I'm putting the 6" Fabtech IFS suspension kit on my truck. Retaining factory coils and arms and putting 33x12.5x15 tires on.
One of my many concerns is maintaining my turning radius and keeping the stresses on shafts and joints to a minimum.
The kit calls for a 4" backspace. I am planning on also using 1.5" or 1.25" spacers on the front and no spacers on the rear.
While this will maintain my turning radius it will also increase scrub radius.
Am I correct in understanding that increased scrub radius makes the wheels roll easier while turning or is it the other way around?
Or am I completely lost here?

 

Bumped...

 

Ok. /deep breathe
The scrub radius may/may not change with the 4" backspaced wheel. Right?
But it will change by adding the spacers.
The larger scrub radius will put more stress on steering bits and wear bearings faster.

So how much is too much and how do I figure out my scrub radius with the wheel/tire combo and spacers?
Is this even something I can figure out myself or do I need someone with a degree in automotive engineering to figure it out?