Putting the cell where in inline chlorinator is currently is the logical place. And I doubt if you will need it again. A floater does work if you do even need to use a tab or two again for some reason. I had a fit trying to get my new Circupool Universal 40 to fit. I think the cell the the same length more or less. As long as you end up with 8.5" or better for a "vertical kit" install when you are done it will work. If you are going to go completely horizontal, then you need 24" The cell and connector (at least on the Universal but I think the others are the same) is 16". You can put the flow switch on a vertical and the cell on a horizontal, or whatever. I confirmed with DSP it's fine to mix and match and even use the cell as part of the 12" you need for laminar flow in the flow switch. (Meaning the flow switch needs to be away from the filter at least 12")
The Taylor K-1766 is the preferred kit for testing. It is a pretty cool little test. It turns yellow like OTO on the chromate indicator, then it turns a cloudy white and yellow when you add drops of silver nitrate measuring 200 PPM at a time until it suddenly turns a brick red color. That is your reading. There is very little ambiguity with this test.
I was pretty surprised that my pool, after only 8 months of using liquid chlorine was already at 800 PPM of salt according to the K-1766. I may have had a couple of hundred PPM from the fill water (I suppose I should check some day) but, if you play with pool math you will see that sodium hypochlorite adds more salt than you'd think. So definitely check it before you add salt.
I bought the maintenance kit from DSP and that got me the bypass cell, cleaning stand.......and..... phosphate test strips..... I figured that I wold get salt test strips like pictured on their site... I almost didn't get the K-1766 because of that.. I am now glad I did.
Good luck... it's a fun toy so far.. I should have mine on line next weekend. I just didn't quite get it all together last weekend.