virtual audio cables and REAPER, getting occasional pops and crackles

I'm not quite an audio wizard yet but I have the following set up:

VB cables: http://vb-audio.pagesperso-orange.fr/Cable/index.htm

Reaper (DAW): http://reaper.fm/

I'm streaming the VB cable output from REAPER to various other applications that accept a mic as input. It all works pretty well.

The problem is, I'm getting random crackles and pops once in a while. We're talking maybe 1 pop or a bit of crackly-static per 10 minutes.

The real problem is I'm recording this content and having cracks and pops in the final recording is unacceptable so it's something I need to prevent from happening in the future.

It's also not something I can edit out because they are happening on top of my voice. It's also not noise or anything like that. It's almost like the connection is being distorted or dropped for a very small amount of time.

Basic Googling has lead me to believe that I need to increase the buffer latency in REAPER.

I'm using WASAPI and I found a "block size" variable that defaults to 512. Its tooltip mentions a larger buffer (block size) will help improve performance at the cost of latency.

At 512 the latency is 10ms. At 1024 the latency is 21ms. For what I'm doing I feel like anything that's under about 100ms would be fine (I'm recording screencasts), but I wonder what other implications are there from raising this too high?

Should I just leave it at 1024 and try recording a bunch while artificially creating CPU load to create a worst case scenario or should I start at something higher?

Basically the pops and crackles are extremely random and I can't determine if it pops until after I've already recorded, so I'm looking for the fastest way to determine what the best block size would be so that they are eliminated in all use cases.

Lastly is there anything I can do to help prevent the pops from happening that isn't related to fiddling with the buffer latency? Would restarting REAPER help at all? Today I had it open for hours at a time and had quite a lot of pops.

Thanks.