The first thing you should look at I believe when considering upgrading from an Handy to an multi-axis device is if multi-axis movement is for you. How?
Use your hand to make said movements.
Afterwards deciding on an OSR2 or an SR6…the main thing is to decide there is simply how many axis of movement do you want? As OSR2 has only two while the SR6 has 5, twist adds on an extra axis. Same with also price as the SR6 isn’t cheap by any means and an OSR2 is cheaper and thus an easier way to see if multi-axis is for you and not regret decisions so hard. However if you like multi-axis and then want to get an SR6 you can reuse most parts of the OSR2 in making an SR6…if your DIY-tech savey which is something else…
When purchasing one of these devices and also an SSR1…you need to understand that if it breaks or has an issue…you are the one that needs to get parts and fix it as while pre-builders will usually give you an warranty period of a few months, anything after that and simply diagnosing the problems will require yourself to take a screwdriver and take apart your device. It won’t be easy for someone who hasn’t opened up and fiddled with tech devices before as it isn’t as simple as triangle hole goes in triangle hole as some bits can go in the wrong place despite them all having their own home. Here’s the tools I’ve needed for my SR6:
https://www.amazon.com/dp/B0001P18MI/ (you’ll only need this for the circuit board)
https://www.amazon.com/dp/B07V5WYXP5/
https://www.amazon.com/dp/B000Y8J7WA/ (I think this is exactly what I got, not sure as I got mine from a local store)
Now comes looking at mounting/fixing the devices of where now that you know what device your getting, you know how much force that device is giving since the SR6 has double the servo’s than the OSR2. So it can more easily shake an stand or an desk even. As a result I would give caution against the floor mounts (I haven’t tried one) you’ve provided since the top of that mount will probably sway badly if the entire thing doesn’t come free from the weights you place on it. (The devices are CHUNKY size wise so allow 30cm of length from the mount to yourself)
Instead what’s best is getting and monitor mount that attaches to your desk which isn’t gas powered and can be fixed into position. I’ve recently gotten this and it has worked well for me: Amazon.com: Monoprice Essential Single Monitor Desk Mount - VESA 100x100, Up to 22lbs, 180 Swivel, Tilt +/- 90, 360 Rotation, Black : Electronics
You can combine/change parts of these desk mounts to a degree usually if you look at them carefully enough so if one has too short of an mounting pole, but the actual holding mount is great then you can order it and an different mount that has a suitable pole and switch the holding mounts to make up the the difference.
There is an option of doing Zalunda’s desk arm since as you may spot it is on an desk pole mount which can be turned upside down to then has it so instead of going only up, it can go down. Making is doesn’t require you to use an 3D printer since you should be able to find someone else to print the parts and send them to you. (E.g https://www.treatstock.com/ I haven’t used this site but looks decent) So you’ll have to just do the assembly alongside getting the non-3D printed bits which usually an hardware store will have or amazon should have.
Now after all that are two more things, scripts and sleeves/onaholes. Scripts that are full on multi-axis are outnumbered a ton on this site by single axis ones, probably at least 100:1 ratio. There’s some single axis which have twist axis added on to them or some multi-axis bits like roll and surge, but not the full thing. So it will take time for your to build up an library of multi-axis scripts to get to use your device to it’s fullest. But useful thing is that you can still use single axis scripts on it so you’ll have plenty of those to keep you entertained in the meantime.
For sleeves/onaholes I believe for the SR6 the weight limit of it so it can move at full speed is roughly 800g but I haven’t personally put that to the test. However speed your aiming for does matter since you can go for a bit heavier if your going slower. HOWEVER (x2) this all depends on the servo’s you use…because if you use an 30kg servo instead of say an 45kg servo then the weight limit of the device is less compared to one with 45kg servos. This is where torque comes into play once more and well in the past when I realized I didn’t know how Torque is calculated…I then went searching around and found this that ended up making me realize that while the servos had an 35kg torque…due to the distance from the servos to the point of placing torque (maybe 10 cm I think I measured of my SR6) their actual torque goes way down to like 3.5kg. (torque divided by distance) Meanwhile getting 45kg servos results in 4.5kg if fully powered as 45kg servos require more power compared to 35kg ones generally otherwise they can’t move as much weight nor no longer beat the 35kg servos in speed. Seems plenty of weight room but it isn’t quite since you go your receiver taking up some of that weight alongside (if you get it) the twist axis servo and stuff there too. Which by the way…no point in getting an onahole that doesn’t fit into the receiver or adapter you get so might be best to check if they fit prior.
As myhandy said, I hope this also helps you in making your decision but I also suggest checking out a few topics around on this site instead of just taking two individual’s words on it all. (We don’t know everything, only what we’re experienced/found which could be wrong)