Will fit right in to the Arca Z1 ball head's clamp (I think I want the Arca with the screw and not the lever, unless those with experience recommend otherwise?).
So that advantage with the RRS plate is that it made to fit and will stay square on the body and will not twist like my annoying inexpensive manfrotto set up. But that plate is next to useless for my 200/2, but I never put that lens on a tripod; it's a handheld lens only for me.
The Arca Swiss Head is considered one of the top ballheads, as is the RRS-55, and Markins Q-Ball M20 (many users and reviewers described the Markins as slightly smoother than the RRS-55, that's why I went that route). FWIW, the Arca Swiss is considered buttery smooth as well. I bought the Markins without a clamp and then I purchased the RRS Quick release lever clamp (B2 LR II: 60mm LR clamp with dual mount) and attached it to the Markins head with the included screw. However, I don't think you can go wrong with any of the top 3 ballheads above. Personally, I happen to like the lower center of gravity of the RRS-55 design, as compared to the Markins and Arca swiss.
Another thing I like about RRS, is that you are not only buying a clamp or lens plate, but you are buying into a totally compatible system in which everything that they design works very well together. For me the ballhead was less important than the interaction between the camera/lens plate and clamp. I use all RRS camera L-brackets and lens plates and I have one wimberley plate which works perfectly with the RRS lever clamp on my ballhead and monopod head.
I prefer the QR lever clamp over the knob clamp. The QR lever is either open or closed, and that is easily determined by just a quick glance at it. If you look at the knob clamp, you can't tell if it's loose or tight. You have to actually check it with your hand. So, there is a tendency to keep tightening it all day. The other thing I like about the QR lever is that, it is not a knob, so it has a different feel to it.
Many ballheads use knobs for tensioning the ballhead or for panning. So, if you are looking through the VF and want to reach down and loosen the panning knob or adjust the ball head knob, then there is no way that you would accidentally loosen the QR lever, because they feel so different. This is not the case if you have only knobs.
Sometimes I also like to rest my left hand around the top of the ballhead and the knob can get in the way. I also have the QR lever on my RRS monopod head because I was afraid that all of the positioning, rotating and twisting about with the monopod, could accidentally loosen the clamping knob.
The other nice thing about the RRS QR lever if you should choose to ever get an RRS monopod head, is that for birds in flight, the RRS head uses a knob for tilting the head upwards, and that knob could also easily be mistaken and loosened for the lens plate clamp knob. With the QR lever there is no chance of that happening.
One word of caution regarding the QR lever, is if you're carrying your tripod over your shoulder, is to make sure that the you don't accidentally catch the QR lever on a piece of clothing (that could actually open it) when you bring the tripod back down to ground level. I have never done this, but I'm aware of it. The QR lever actually has a tight fit against the clamp, so there's probably only a very slim chance of catching it. Some QR levers like the Arca Swiss brand have a lock, which is a nice touch.