Before I conceived of the Creek, I had a 9'2 Flow, 8'10 Flow and 9'1 Acid, 9'4 Acid.
9'4 Acid was my go-to
I couldn't ride it in full New England wetsuit gear, so I tried to do a mash-up of my favorite boards.
The goal of the Creek, was to get Acid like performance, with some "stability tools"
Some highlights of Flow and Creek:
The Flow may be a bit snappier on the wall.
The Flow will be more stable at equal volume.
The Speeed tail on the Creek, gives it a sweet, tight carve and it handles size better.
The Creek is very fast... after getting it, the Flow was noticeably slower and harder to get the same performance.
When in doubt of conditions, I always take the Creek.
You fall right between sizes on the Flow
8'1 x 28.5 Flow at 100 liters
8'4 x 29 3/8 Flow at 110 liters
BUT... you will probably find 100 liter Flow equally stable as the 105 liter Creek.
Creek:
8'4 x 28.5 Creek at 105 liters
which is right at 1.3 weight to volume for your weight.
I don't recommend any smaller, as I feel it rides better at one size bigger than you might think.
But being quite a bit younger than me, you may want to question my feeling on that

Bottom line, you may find
the Flow to be a bit more shortboard snappy
The Creek a more serious performer.
James Casey seemed to like his, when he took 3rd in the Aussie Titles, on his 7'7 Creek