Yes, the quickest powder measure change would be to buy another case activated linkage kit. See the link.
http://www.midwayusa.com/product/802477/rcbs-uniflow-powder-measure-case-activated-linkage-kit
I would get another RCBS unit as opposed to the Hornady unit as the parts are interchangeable within the same manufacturer.
Depending on the number of different cartridges you load, you may want a powder drop die for each cartridge so that you do not have to re-adjust the die with each change. Then you would need the pistol powder expander for each caliber you load.
You didn't say which progressive you bought...makes a difference as to what advice you get. If RCBS Pro2000 or Hornady AP, Chuck's on the right track. A little more info to hopefully clarify things for you:
All you need is the linkage-kit that Chuck just linked for you from Midway above, to use the Uniflow on station 3. It comes with drop tubes for everything, no other parts needed.
However ..... if you want to expand and charge together on station 2, (so you can open up another station for things like lockout dies, bullet feeders, separate crimp dies) then you need powder-through expanders as these from RCBS.
http://www.midwayusa.com/find?userSearchQuery=RCBS+powder+though+expander
Using station 2 on a Pro 2000, or any other progressive with exchangeable tool heads, means the Uniflow (or Hornady P.M.) is mounted on the tool head. This explains why Chuck thought you might want extra powder dies to mount on all your pistol tool heads (or in extra bushings if Hornady) if you want the quick-change between calibers, you have two options and one is expensive: a new P.M. setup mounted to each tool head (Dillon style), or extra "powder die assemblies," Hornady/RCBS style. On a Hornady AP of course, you mount your extra powder dies, preset to a depth for a particualr caliber, on extra bushings. (Notice the Hornady assembly sold as a kit (Quick-Change) as well as the Hornady powder-through expanders on the following link)
Hornady Parts.
To make this as clear as mud, actually you
can use Hornady parts on the Uniflow. Their linkage, their "quick-change powder dies", and their expanders.
BUT its all or none. Think assemblies. Hornady assembly parts are not exchangeable with RCBS's. But you can use the Hornady case-activated assembly on a Uniflow just as easy as the RCBS one. Pro 2000 users like me did just that before RCBS finally saw the light and provided powder through expanders of their own last January. I use both.
I do prefer the RCBS expanders though. They are more versatile to expand a little or the lot (necessary for bullet feeders). The Hornady expanders are designed to be pushed in all the way, to expand for the bullet feeders.
The only hang up with RCBS is that they don't offer a Hornady-like "quick-change kit" discountable at Midway, et al., to mount on each tool head. To get that you have to email or call up RCBS and order the separate part, called the "Powder Die Assembly". At least that is better than what they used to offer....each part of the assembly ordered separately.
Hope this helps. IT took me 10 edits to even make it clear to myself!
Which Progressive do you have....very curious.
Just a bit of trivia. Yes the powder measures are similar. RCBS invented the Uniflow, Hornady licensed the design from them. Hornady came up with the first case-activated linkage for the design that really worked well. We don't want to talk about RCBS's first attempts. Anyhow RCBS licensed the Hornady linkage. For all I know the two licenses could have gone away, canceling each other. Hornady would have the advantage there if RCBS wanted the linkage bad enough!