Killer, eFish (if I may be allowed a small pun)!
Killer indeed... many, many, many times over!
Since you asked, I'll give you my conclusions on shotgun reloading (and, by extension, shooting).
I don't think weighing powder and shot charges will ever merit for any 'standard' scattergun load,
especially if you are planning on doing a fair amount of shooting. Simply put, you cannot pack the shot pellets with the same precision in every load, so there will always be some inherent variability within your pattern... perhaps using some specific stacking shot (like Winchester blindside)
might be a way to get around this,
BUT then there is the problem of "fliers" spinning out of the pattern because the pellets aren't round (which is why high end lead loads use a buffer to prevent pellet deformation).
The randomness of patterns mentioned above also plays into chokes... pattern consistency (for any given diameter of choke) is based more on length of taper than anything else (longer tapers are better). However, I would guess 99.9999% of birds not downed (within range) had little to do with uniformity of pattern, rather they were (primarily) due to poor shot placement (i.e. shooting behind, above, below, etc.) or (secondarily) due to an incorrect choke application for the task at hand (i.e. being too narrow or too wide)... I know 'a guy' (AHEM, ahem) that forgot to change out his improved cylinder from the previous fall and was scratching his head when he was not putting turkeys to rest the next spring.
As we have discussed elsewhere on the forum, the hunter/fisherman that plays to his/her points of confidence will almost always perform better in the field... so, experiment, have fun, and find what works for you.
(*It should go without saying that a print test of slug loads will prove the benefit of individual weighing, so I'd definitely give the nod on being fussy if/when you load these.)