Self-close or soft-close? They're two different things.

Self-close - grab the drawer and snap it shut

Soft-close - grab the drawer and gently close it

While soft-close isn't a necessity, it's very nice to have - whatever the size of the drawers! Soft-close prevents drawers from being slammed and, potentially, causing damage over time (or causing arguments!)

What is a necessity, IMO, is full-extension; so whatever you decide, be sure the glides are at least full-extension.

Yes, I mean both soft- and, by implication, self-close. The Blums I'm Looking at are also full extension (Blum Tandem Plus Blumotion Slides)

http://www.rockler.com/blum-tandem-full-extension-drawer-slides-with-blumotion-slides

I really can see the benefit of having them. I'm starting to get used to how massive they are. And they seem like they might work with our current slide-mounted drawers but the technical specifications say that the bottom of the drawer needs to be recessed 1/2" from the sides of the drawer. Ours are only recessed 1/4". But I don't see why 1/2" of recess is absolutely necessary, as long as there is enough vertical clearance for the drawer to slide into the drawer box of the cabinet frame.

Here's an unintended consequence of having all soft-close in our kitchen: we've gotten so used to being able to give doors/drawers a quick shove that I forget they're NOT in other parts of the house....and SLAM/BANG! goes the powder room cabinet door. If it's not a big deal $$ and installation-wise, put them in everything. :) I'd also think you'd want the Blums for your eating utensil drawers, as these basic drawers are likely used the most every day.

Save yourself some $$ and look at AHTurf.com. I buy all my glides from there for less. I've also find glides at the reuse centers, but they're normally missing brackets and the drawer release thingies. I can pick them up at AHTurf for very little.

Your drawers need to accommodate that orange release thing at the front of the drawer. If you can do it with 1/4" great. It wouldn't show behind your drawer front.

Remember, If your opening is 12" wide, your drawer needs to be 11 5/8ths. You only need 3/16ths on either side. I go with 1" for the bottom. Weight in them lowers them a bit and they can rub. It's better to have a little leeway.

I have retrofit. 3, 36" stacks, and 6 other cabinets into drawers.

Now, that said. I'm looking at some very shallow drawers where I need that single inch. I'm looking at some of the side mounted, full extension. They need the 1/4" on either side, but I gain a lot in depth.

I like bloom and don't want to really use anything else.

CEFreeman_GW DC/MD Burbs 7b/8a Thank you for the tip on AHTurf - great website and much less expensive than my other options for the glides.

Regarding the 1/4" recessed bottom of the drawer box, couldn't our handyman/carpenter find a way extend it by an extra 1/4" at the front only so that we can mount the slide clips? Same thing with the sides, our drawer box has more than 3/8" space between itself and the cabinet frame on each side. He can add extra wood on the inside of the frame to make the gap with the drawer box the required 3/8" on each side.

Your drawer box needs to match the specs. You can't just add wood to the sides and expect the Blum runner to work. The space needed on each side of the drawer is also dependent on the thickness of the drawer side. If you use a side-mount slide, then you could add something to the side of the drawer if you needed to. But your drawers might be too wide for that, so you really do need to measure your drawers and checks the specs.

I neglected to say that Barker has great instructions for measuring Blum and another, side type. Other than that, you'd have to dig the specs out of the manufacturer's website.

You're getting into some tedious work. I would consider either having him remake the drawers completely, buying new ones, or getting glides that fit better in the space and with the drawers you have. This is getting to be way too much work than I'd take on, and I will fuss with something for months.

The one and only modification I'm going to make to a drawer to make it fit my space, is on a 17" deep drawer. The next glide is 18" and they must match. I'll put a piece on the back of the drawer above the notches, and drill the little holes for the glides. But that's about as retro on drawer boxes as I'm willing to go.

One cabinet I'm retrofitting, is going to get drawer boxes I got at a reuse center. Nice and deep, but definitely not Blum Tandem ready. They're going to get the old fashioned Blum 230 (or KV) types. They'll only hold towels in the MBR, so I don't care. Better to have drawers than 2 reach-in cabs. They're getting inset doors, too. It's A.M.A.Z.I.N.G. how much cat fur will settle into a cabinet between an overlay door and its cabinet box.

Enough about me. I would suggest you either reconsider this endeavor, or how it's to be accomplishd.