I think you got an good one there, I have the 300 base, and with the JR head, you get two balljoints that gives you great flexibility, I also have the standard Jr, and with only one balljoint it is not so flexible, so it tend to be sitting more than the 300.
Wonder a bit about the weight on the 328 though?, my 300 is heavy, but from the pictures it looks like it maybe is not heavy?, lighter type?
At any rate, I like everything heavy, so I bought this for the 300:
http://www.panavise.com/index.html?pageID=1&page=full&--eqskudatarq=13 (way overkill), and this one for the Jr:
http://www.panavise.com/index.html?pageID=1&page=full&--eqskudatarq=20 to make things not move around. (The 300 doesn't move in the first place, but I didn't know that at the time I ordered.. )
and £20?, ridiculously cheap, these costed me very much, I could not find them in Norway, so had to buy from US..
This one you will find need for I guess:
http://www.panavise.com/index.html?pageID=1&page=full&--eqskudatarq=228 (I think you can 3d print it also)
And these are nice to have, but not necessary
http://www.panavise.com/index.html?pageID=1&page=full&--eqskudatarq=23