I have several and I think most folks here are just telling you what they have more than what they recommend.
For instance, I have a Saker too, and it's a really nice can, but it's probably not what I'd recommend unless you wanted a hard abuse military type can. Sico does make good cans in general.
I also have a couple of SDN6's and I wouldn't recommend that one for pretty much every reason EXCEPT how well the can itself actually works. Which is pretty well if you're wondering but the mounts alone do it in, let alone CS and a failing company. So it's not just the can you're shopping for.
Unless you're gonna do mag dumps or fire lots of fairly rapid fire or use on large caliber SBR's, I'd say go with TBAC. Mounts are simple and solid. The 6.5 Ultra 9 will work best on those 6.5's, I have one and I use it on a 20" Grendel and it makes it sound like a poorly suppressed .22 --it's very quiet, very light, very well made. Weight isn't really noticeable on a fairly heavy rifle like mine and most noise comes from the sonic crack. A 30 Ultra 9 would work well too and cover the .308 as well as the 5.56 (and you can always add more later, people rarely stop at one can, just so you know). If the 5.56 will see harder use, TBAC makes a steel hard use can and the Sico Saker is another good hard use can and prices usually aren't too bad, especially when they go on sale. Here a 7.62 Saker would also work since you can get different end caps for the Saker and it's quieter with 5.56 than is the dedicated 5.56 can. So it's flexible. And heavy. KAC makes one of the best all around cans but it's an expensive setup and almost suredly not what you want in your first can.
I have a 30 Ultra 5 also and on a Grendel it takes the noise down to "tolerable" and works really well on .300BLK SBR's. It's nice, but probably not what you want for your first can. I also have a 30CB9, the model prior to the Ultra. It's nice too, not as quiet but it too suppressed the 6.5 well but with a deeper tone, which is what usually happens when you use larger bore cans with smaller bore rifles. Many people prefer the deeper tone. There's also the Ultra 7, 2 inches shorter than the 9. I'd go with the 9 though for pure performance, which is what I'm figuring you're expecting. Most people go for length on later purchases (and then I'd get the 5).
I'd for sure get the TBAC Ultra 9 unless you're gonna be doing mag dumps. You can also ask the mfg. about it, Zak is on here all the time and takes care of members. You won't be let down.