You shouldn't need to worry about how much dilution it causes. You should instead ask yourself first if you are linking out because that's a recommended best practice or if it actually creates relevancy between your site pages( read site architecture).
Too many people are focused on linking out to 'authority' sites without even asking themselves first:
1) Will it cause visitors to be distracted and bounce= lower conversions
2) The URL I'm linking out to, will it provide value and add TRUST to how my audience perceived me?
3) Am I doing this because I want good on site best practices as recommended by all the gurus and Google shills, or does it really make the customer journey on my site much better?