Another thing I forgot - using D3D Fullscreen and only using Bilinear (normal, non-PS 2.0) in MPC-HC also helps reduce CPU utilization...which means getting away with higher settings in SVP.
Take note that the settings I posted are optimized for minimal artifact since the 25fps content I watch is highly susceptible to said artifacts (motorsports). For 24fps and 30fps I normally use Uniform + Simple Lite instead which is actually smoother but gives more artifacts, though they're not really noticeable on the 24fps and 30fps content I watch.
Another key thing is that, since you're doing software decoding of the video stream itself, using a codec that's light on the CPU (i.e. MPEG2, FLV1, etc) can allow you to use higher settings in SVP. In particular, I can get away with using Uniform + Standard for 30fps, 25fps, and 24fps content in such situations. Heck, if I don't plan on watching a video for a while, I'll even sometimes re-encode a video, such as a 1080p VP9 video from YouTube, into 720p FLV1 @ Quantizer 2 (the filesize is like 6-8x larger, but it doesn't matter when I don't plan on keeping it anyway)
This is all assuming 720p videos and 60hz monitor refresh rate of course.
EDIT: Just remembered one last thing - you can also save a few more percent of CPU utilization by making sure that yous "Default Sampling Rate" in the Windows control panel matches the sampling rate of the audio stream in whatever video you're watching.
EDIT 2: For most use-cases H.263 is probably the best choice in terms of re-encoding since, at Quantizer 2, if only has 2% more CPU utilization than FLV1 on SVP-intensive content and 8% smaller filesize, plus for other devices it has compatibility with the MP4 container not to mention HW decoding capability if available.
EDIT 3: ...except if you're encoding directly from VP9 via Avidemux, then there's some weird issues with SVP not working correctly with specific codec-container combinations. The ones I find work are Mpeg4 ASP (xvid4) with MPEG Quantization or Mpeg4 ASP (ff), both in an MP4 container (and only an MP4 container, using MKVtoolnix after-the-fact does not work correctly) or FLV1 into an FLV container (which does work with MKVtoolnix, so that'd be the most flexible). Just remember that Avidemux doesn't like Opus audio, so you usually have to deselect it via "Audio" -> "Select Audio"; for MP4 you'll need to provide an external AAC/M4A/MP4/MP3/AC3 audio stream for Avidemux to add to the video.
EDIT 4: Just realized another one - setting processing threads in SVP to "5 threads" seems to give the lowest CPU utilization without resulting in decreased SVP performance (like if you set "2 threads", SVP won't run at full speed even when your CPU utilization is like 30%).
EDIT 5: Go figure, it turns out that non-PS 2.0 bilinear in MPC-HC is actually less CPU-intensive with weak GPUs, so use that instead!