Backing Plate Size & Counter-weight Size Selections....

[Budha]

This may be a n00b question, which I am but.....I did some searching/reading on here and couldn't really find any help in this area for selecting a backing plate size. For a noob I've come to the conclusion that a 6" backing plate/6.5" pads may not be what I want or what my 6" PC 7336 (listed 3.7A 2,500-6,000 rpm) will like. 

Now, do I go with a 5" backing plate/5.5" pads or the 2.875" backing plate/4" pads? As of right now (after some reading), I'm leaning towards the 4"pads/2-7/8" or a 3" flexible backing plate, not sure of brand yet.

Also, let's talk counter-weights. I currently have a 6" counter-weight, what size will I have to drop down to accommodate the smaller backing plates. I'm guessing different manufacturer's backing pads will be different but throw some ideas out for me.

Mind you, I'm just looking for entry level results and convenience - right now. And excuse the n00bie questions. 

[Too Stroked]

You'll get more correction ability with the smaller pad / backing plate due to the higher speed that it will rotate. (Smaller diameter = higher speed + higher torque.) The smaller pad will also fit in tighter spaces. But, the smaller pad will take forever to do the average vehicle. (For some of us OCD types, that's not a bad thing.)

I use a 5" backing plate and 5.5" pads on my PC. You always want a pad slightly larger in diameter than the backing plate so you can't damage the finish by mistake.

As for the counterweight, I'll admit I cheat here - and I'm not sure if it's correct, but I use the 6" counterweight with a 5" backing plate. My theory is that swinging a larger counterweight with the smaller pad will give me a little extra oomph. Let's see what other say.

[sscully]

I can give you the easy answer on the weight. 
Even though it is marked as plate size, it is really weight of the pad / plate comb that the counter weight is used for.



EDIT : The bottom numbers are 125 g to 135 g.

The pad size is a bit fuzzy, for an answer from me.

For doing correcting, you are going to want to go with a 4".  Maybe 5" or maybe 3".  The PC generally works defects better with the smaller pads. 
Now comes the fun part ( that JP, Tom, etc  can answer better), should correcting with anything smaller than 4" be done at the novice level ( and that is including me, you saw the bone headed action on my part for the paint ox - documented proof that I know about a thimble full of detailing experience ).
I just got my 1st 3" pads today, and have not used them yet.  I am fairly comfortable with working defects with a 4" pad. 
I have ordered some 12 AWG bun sheets that I am going to have painted with base / clear in silver and black ( and the same color as my F150 and the Mrs G6 ) for something to practice on.  i am going to use the 3" on that before I go after a car.  Given the DA should be safe, getting to a smaller pad might get me in trouble with the wrong product on it.  I also have the Opti MF pads ( cutting and polish ) in 3.25"

I don't have an extra 4" backing plate, but I have a 4" orange constant pressure pad if you want to try one.  This is medium cut, just above yellow and more aggressive than Green / white.  I use the Lake Country Color codes for pads, as those are what I prefer to use in foam.