With my Sony A7RM3, I wanted to have an extended pinky grip and an L bracket all in one: the RRS solution was perfect for me.
My fluid head however, the Manfrotto 502ah, required I use their proprietary camera plate; one that was a hassle to put on and off every time I wanted to use it.
Kirk Enterprise Solution's bridge adapter was just what I needed, replacing the original fluid-head head with an adjustable arca-swiss compatible clamp. Unfortunately, their clamp size (4.6") is too long for the RRS plate. So I had to buy the 2.6" version (WITH the square lug).
Now, everything is just as I want it!
Links (non-affiliate):
RRS L Plate: https://www.reallyrightstuff.com/Alph...
(yes, this is for the Sony A9, but it's identical to the Sony A7RM3 one - RRS assured me, plus it was in stock when I bought it)
Manfrotto 502ah: https://www.bhphotovideo.com/c/produc...
KES Bridge Kit: https://www.kirkphoto.com/quick-relea...
KES 2.6" Clamp WITH square lug: https://www.kirkphoto.com/quick-relea...
Watch video Fluid Head Setup for Photography, Kirk & RRS online without registration, duration hours minute second in high quality. This video was added by user Alex Cardenas 30 July 2021, don't forget to share it with your friends and acquaintances, it has been viewed on our site 1,85 once and liked it 5 people.