Keep in mind that this will be a very long and thorough review, so if you are looking for just a quick review of it, check my TL;DR down at the bottom. With that being said, let me start-
I will say that this is my first rodeo with plasticizer restoration/addition. I bought a 16 ounce bottle of the DBS to restore some of my toys that have lost their natural plasticizers over time, and to enhance the softness of others as I have become spoiled to the softness and springiness of Inflatable World toys but have acquired plenty of consumer stuff that I want to continue to enjoy.
So far, I have treated 6 different toys (a Poolmaster hippo, Intex Lil Whale, two beach balls- one 20", the other 36"; a Bestway seal, and a small Rinco dolphin that lost its softness after plenty of snuggles and play). Even with softening that many toys with it, I still have half of a bottle left so for anyone wondering how much they will need- well i'd still recommend the 16oz the most as you will get the most product for the cheapest, but it will last you through quite a few restoration/softening projects.
With that out of the way, I will say that I treated some toys externally, and others internally. Personally, I'd actually recommend external application with DBS unless you measure how much you are adding based on the size of the toy and can adequately get it equally distributed inside on all surfaces. It's safe for virtually all paint including on some of the cheapest toys- the only paint issue I had was on my Intex Lil Whale where it tried to smear the white paint on her belly some during application, but only in certain spots so it might've been an issue with how the paint was applied during the manufacturing process and not exactly a reaction to the plasticizer. Of course, I'd advise to test in a small inconspicuous place on the toy if you are worried about this!
Next, it is very fast acting. With external application while the toy is fully inflated (which is as easy as cleaning the toy with a microfiber cloth), it took less than an hour for noticeable absorption in a room near 70°F, and within 24 hours it was fully absorbed into the toy and results were noticable. For deep softening like I wanted, it does take 2 to 3 applications on larger toys, but on smaller toys just one application should be enough.
This is why I recommend externally applying it, as you can eyeball how much you pour onto the cloth yet it will be applied equally. It doesn't take much either, just a quick wet spot on the cloth will cover pretty much an entire Intex Lil Whale for example, so start small and wait for full absorption before deciding whether it needs another round or not.
For smaller toys in particular, be very careful as you CAN add too much and actually make the toy too soft, which will affect the integrity of the seams and cause leaks or worse. So for toys smaller than an average ride-on, always apply external and do light coats! Next, the liquid itself is almost like water in terms of thickness, so keep that in mind so you don't accidentally pour out too much. For storage of the used microfiber when done, I recommend machine washing it afterwards of course but in the middle of a project, be careful not to lay the cloth on anything plastic as since it is a plasticizer after all, so it can soften and even cause damage to plastics including hard plastics, which will become brittle and crack after prolonged exposure.
Lastly, while DBS isn't safe for plastics you don't want to soften, it is quite safe for humans and though I recommend wearing gloves during handling as it could irritate your skin, it's not going to hurt you if you get some on your skin accidentally. Just be sure to wash your hands/wherever else you get it on you with a good hand/dish soap and you should be fine.
TL;DR: DBS is fast acting, easy to apply, has a good safety profile and is all around great for providing a deep, springy softness. Overall, I highly recommend both DBS and Vinyl Vibe Studio for all of your inflatable companions' repair needs!
I have 10 years experience with ATBC and after just first toy treated with new plasticizer I have to say that the DBS is definitely better. It soaks similarly fast but the result is much more even, better controlled than with ATBC which sometimes resulted in overplasticized sticky areas. Absolutely no issues with paint makes it easy for application from the outside.
This plasticizer softens toys quite a lot very quickly, and seems to not harm the paint. 10/10