Bow thruster - fairing tunnel

[thewrenchking]

Hello all.
In the process of self installing a Sleipner bow thruster on my Westerly ocean lord. 41ft monohull.
Followed all manufacturer's guidance for layout as close as possible... The one thing I'm hung up on. OEM states that when bonding the tunnel to the outside, to build a fairing to smooth water flow.
"As a rule the back of the tunnel should not be visible when viewed from the front". Logical enough but in practise... The geometry of my bow means this would be a massive structure. What's worse case scenario for speed of I get this wrong and or compromise a little... Generalisations of course.
Many thanks!