Thinking about cutting my 3 wood to hybrid length ...

[Stuffs]

General rule of thumb is for every 1/2" you cut off, you lose about 3 swing weight points.  Most people will start noticing a different with anything over 2 sw points change.  It will take about 6 grams on the head to make up the 3 swing weight points back.

Cutting 3" might be too much.  Try using lead tape and add about 6 grams to it.  Then grip down half an inch and see what happens.  Add another 6 grams, grip down another half...and so forth until you find a comfort zone where you're hitting it well.  That way, you can get a true assessment as to how the length of your 3wood is affecting your shots/ confidence while keeping the swing weight the same.

I do believe woods and driver stock lengths are just too darn long for 90% of players out there.  I never understood why they just get longer and longer.  (well, I do but lets not get into that).

Hitting it solid and flush trumps the marginal distance if any, gained with longer lengths.

The shorter the club, the flatter the lie will be, meaning that it needs to be bent more upright to have the same lie at impact as it once was.  But with woods, that isn't much of an issue because of the aggressive camber the sole has.  Lie angle is crucial in wedges and irons, but not so much in the longer clubs.  Cutting your 3 wood about an inch or so wouldn't affect the lie enough, unless its already laying too flat or toe down right now, which I doubt.

If say you find going an inch short seems to work for you but you don't want the looks of lead tape, you can always tip weight it.  You local club repair shop should be able to do that for you at not more than $20.  Golfsmith makes a rubberized tungsten tip weight that's flexible and is perfect for graphite shafts.  They make an 11 gram version which should be suffice to keep the same swing weight after cutting an inch.