since this is your first suppressor - i recommend instead of specializing to go with something thats more of a jack of all trades.
that said - get a silencerco hybrid 46. i have a few friends with them and they're fantastic with everything from 556/223, 9mm, 450 bushmaster, 308 and others.
itll handle your small caliber stuff just fine - and is capable up to 45 caliber (45-70, 450 bushmaster, 458 socom), as well as being rated for magnum cartridges up to 338LM.
dont worry about the smaller endcaps - shoot it first with the smaller stuff before you punk down the $ for them. not saying it doesnt help, just saying you dont *need* them and... it puts you at risk of forgetting you had the smaller endcap on when you switch to a bigger caliber and ending up with a sad day instead of the *pew pew grin*
being able to utilize your suppressor on a 9mm carbine with 147gr subs because you got something in 30 cal is a real sad panda moment lol
trust me when i say once you start shooting suppressed - you wont want to shoot unsuppressed if thats an option. and having to go "aww man i cant use this on my _____" really stinks.
hth