As others have pointed out, grips can be modifed to work or simply swapped out for a pair of grips that will accomodate your speedloaders.
Speedloader prices range between $9 and $15 most places. If you're not sure which type you'd prefer, buy one of each and practice. Find the one that suits you best and sell the other one to a friend or shooting buddy.
Back in the 70's when I went through training, the instructor forced us to reload from a back pocket or belt-loops. This was to get us used to "the basics". One woman in our class was incredibly fast with either method because she constantly practiced. From loops she did two at a time and was not measurably faster than using Bianchi Speed Strips (which were only about 5 years old at the time).
When we did get to speed loaders, we found out just how much time they saved over manual reloading. Average manual reload time was 7.2 seconds (excluding Debi who averaged just 5.3 seconds!). Speed strips dropped that class average down to 5.4 seconds and speedloaders (excluding one guy with a premature release issue
) got us down to an average of 3.8 seconds.
Safariland vs. HKS
Use whichever you are comfortable with. Some folks complained about HKS "releasing" rounds in a pocket. I've never had that happen in a jacket/shirt pocket or a pair of slacks. I could see it in a pair of jeans or tight fitting pants however.
On the other hand, I've twice experienced Safarilands releasing in a jacket pocket because the loader was pressed up against something (car center console probably).
I typically use HKS because they're almost always available and I'm used to them. They're also available in more sizes and calibers.
Be sure to practice with them! Use snap-caps or have a reloader make you a dozen FMJ cartridges with no primers for practice.
Practice until you can load in the dark. Keep your gun up chest high while reloading so you can see movements around you. And practice while prone, supine (on your back) and while running.