wait a second (i use an object on the table as a visual cue) before performing 3rd dash, if guard swings (75% chance), don't dash after the grub, instead pogo dash pogo, if guard drops (25%) dash immediately after hitting the grub, saves 0.6 on a swing and 0.7 on a drop compared to having to wait for 2 swings
[you can also get a pogo on the sentry before going over for soul]
[edit you also don't need to wait if you get a swing but shockwave is mega uncomfy]