As of EnhancedVisuals v1.0.12 mc1.9-1.10.jar, when player is low on hearth, the blur is way too intense to do anything in the game.
Can the blur be much more light?

You can configure each effect and its intensity inside the config file.

• yes, if you multiply a number by zero it will be zero.
• everything is measured in ticks
• the 'min' value will always be added. 'additional' is the maximum additional duration:
  min + additional * random()
  that would mean if we have the following values:

S:splashAdditionalDuration=30.0
S:splashMinIntensity=10.0

the duration of the splash effect will be from 10 ticks to 40 ticks long.

• Same goes for intensity. The higher the intensity the less you will be able to see (means screen gets even blurrier).

I'm missing the option to adjust the number of hearts left that start triggering the effect.

Also, options are unclear to me, notably:

alpha = normalAlpha * alphaFactor [range: 0.0 ~ 1.0, default: 1.0]

S:alphaFactor=1.0

=> does 0 mean no overlay at all?

# heartbeat duration [range: 0.0 ~ 10000.0, default: 10.0]
S:heartBeatDuration=10.0

=> is it the length of 1 flash or the delay between 2 flashes? is it measured in ticks or ms?

# heartbeat intensity [range: 0.0 ~ 10000.0, default: 50.0]
S:heartBeatIntensity=50.0

=> which intensity? is it the lighting intensity of the effect?

# maximum additional splash duration [range: 0.0 ~ 10000.0, default: 30.0]
S:splashAdditionalDuration=0.0

=> what's triggering the additional duration? is it always added?