Hi Sacguy71,
Nice jam! :-) Sorry, I don't have myself the Octatrack but if I am not mistaken then the Octatrack doesn't have specific CVs and gate outputs so you are forced to do that via MIDI and that with that Doepfer module... indeed then doing the controlling of your modular by the A4 is a much better way to go I think.
Then this time buy directly a big case then you got enough space for a while. The Doepfer A-100LMS9 is a cheap case if you calculate it down on a per HP basis and with 3 rows of each 168 HP should keep you going for a while :-) I use myself the A-100LMS9 and I am pretty happy with it, still also that one gets filled up one day...
Have fun and kind regards, Garfield.
For review reports of Eurorack modules, please refer to https://garfieldmodular.net/ for PDF formatted downloads