The graco contractor guns are two finger and the SG3 is 4 finger. I sprayed thousands of gallons with the contractor gun but found I like the 4 finger gun better. There is less spring pressure on the SG3 and you have more fingers to do the work. Are the walls going to be the same color as the ceilings? I would shoot pva/primer first, then spray the ceilings and then spray the trim and roll the finish on the walls. Backrolling is best and I would use a 515 or bigger tip for that. The size of airless will determine your max tip.
I used to run a Speeflo hydraulic pump that we could run two guns with at least 515 tips. A couple years ago I had 8 bathroom buildings to clear coat and paint after we built them so I picked up an x17 or x19 at home depot, on the company dime. My Graco 190es needs rebuilt again, but it was the smallest contractor airless they made 20+ years ago. It pumps on the up and down stroke. I think the new graco was one step below mine but the bathroom buildings were small. It worked fine with a 515 to spray and backroll primer and paint on the block walls. The worst part of the new graco is that it sometimes didn't want to pump again after sitting and needed to be flushed out with a garden hose. Better pumps like my 190 and my Speeflo air powered airless, have no problem pumping clean water from a bucket to rinse and then pumping all the water out of 100+ feet of hose when done. Use a 3/16" whip hose at the gun and make sure you have a swivel gun. The SG3 has a swivel and the lower gun does not.
Baseboards are a ***** to spray because there is always dirt left on the floor, no matter how well you clean. It is also easy to lay down too much paint on that kind of trim. A 413 tip better for that sort of stuff. The first number is half the fan width and the second is the diameter, so 8" fan at 10-12" and 13 thousandths opening. They also have fine finish tips but I have only used one with oil paint.
For drywall work and interior, I only use lambswool roller covers. Roller covers are very easy to clean, if you know how. It is very rare for me to let one sit in paint overnight. Brushes and rollers need to be cleaned out each day to get a nice finish and be able to freehand cut in........I almost never use tape when brushing and rolling. If you spray primer, ceilings, and trim paint, you can easily brush and roll the walls because they will already be sealed. It is easier to freehand the wall color next to the trim and make it all look good or use tape if you must.
It takes a lot of practice to get the coordination for spraying and knowing how much paint to lay down and even after doing it for almost 30 years, I would rather spray and backroll interior ceilings and walls becuase you get a more even finish and don't have to worry much about your spray pattern. It is possible to spray and backroll with only one person. The power fed rollers are a pain and I hardly used mine. The idea with backrolling is to spray enough paint that you hardly have to dip the roller. Most people don't use nearly enough paint when rolling anyway. When doing brush and roller work, my roller is so wet that it almost drips and then I slather the paint on the wall and dip again every roller width or so. The first pass slops the paint on the wall somewhat evenly and after I have 4 to 5 feet of width of the wall covered, I roll over it again smoothing out the paint and working it in. You should not hear the roller and it should not fling the paint. There should be a solid wet film on the wall but not so much that it runs. It also does not take a lot of force, but you need a good roller pole that is adjustable and a good amount of paint. When it is dry, the nap sticks to the wall and splatters and it takes more force. It sounds messy, but when done right, there aren't a lot of drips. On new construction, it is no problem to drip some on the floor. Brushing is the same. So many people use very little paint and treat it like they are dry brushing. You can't water the lawn without soaking the grass and making sure it is saturated and getting a good film thickness and coverage with paint is the same. The key is getting a nice finish with your final strokes.
When spraying, I always thin the paint so it flows out. For Behr paint (it acutally works well and I have used many brands) I might add half a gallon or so of water to 5 gallons of paint. Just go by feel and use just enough to make it flow out but not run. If you use it straight, the sprayed areas will have orange peel or end up too thick once it does flow. You can try not thinning it and see how it goes for backrolling. I have not tried many of the new tips since I don't paint often anymore, so I can't say if they do make a big difference in overspray or finish quality. The spray gun should be within a foot of the surface and I suspect that people who have a ton of overspray may be too far away.
