Keeping it light-tight, so that it can be used with the lights on, I just rock-it sideways, but gently, using the base left edge and the right base edge as pivots for a small swing. The movement is very close to rocking a tray sideways. Since I do semi-stand, when it's time to move the developer a bit, I close the lights and open the lid, raising and lowering the film holder core two or three times. Then I close the lid again.
You cannot do inversions with this tank, nor can you agitate it too vigorously as the liquids will come out.
The frame wouldn't allow anything extra to be thrown in. At least without damaging your film. Unless you attach it to the frame somehow. But would then act as a baffle, creating a current inside that you probably do not want.
I stick to my Jobo or SS tanks by the way. Ruined an entire tank full of negatives because of uneven agitation (which was according to manufacturer's directions).
For SS, I use double-120 (4x 135) reel tanks. Two sheets emulsion side out portrait orientation into tank. No rubber bands or anything. Fill the tank full in case the film rides up the tank during inversion.
The reason I only use my Yankee for semi stand is that it very slow to drain and with the light tight cap on I can only rock back and forth and side to side so the negatives are prone to uneven development. I have attempted couple of different alterntavie methods of filling the tank, such as fill and drain with the lights off, messey I used raditator hose tape to tape the lid and fill hole so I could invert the tank, just not worth the hassle. If I have only just one or two negatives I use a old Unicolor film drum, for 4 or 6 a set of daylight tanks that use hangers, they take about a quart of chem, and for more than 6, standard hard rubber tanks with hangers. I have never got the hang of using trays.
The Nikor tanks show up on ebay all the time, and some of them end up selling pretty cheap ($100-ish). I use one and really really like it, but then I've always been a fan of stainless tanks and reels.
There's one on there right now for $120 buy-it-now. Has the little zig-zaggy retaining band, but not the little cap for the lid.
I never really thought these Yankee and similar tanks were a good idea, but I had one around and needed to do couple larger runs so gave it a try. I have to say that I'm pretty happy with the results, and I'm using aerial rollfilm stock which is tricky.
But I never pour in or out of any daylight tank (except on the Jobo). I load the holder (full run is 12 sheets) and drop it into the developer in the dark, then put the lid on and process with in room light. I give vigorous rocking agitation in the direction indicated on the tank. I fix in an open tray; just more convenient to me that way.
You can mix up a gallon of any kind of tank developer like DK50 and replenish very cheaply. I'm using some old GAF (Ansco) developer.