It's getting there, yep...I still think the Maths would be preferable to just the single VC Slope of the Contour because of all of the internal routings you can do with it to reconfigure it in some very complex ways. Why not pull the Contour in favor of a Doepfer A-140-2 or an A-141-4 for some additional "proper" ADSR EGs? Also, you might consider a comparator or two, since adding those plus a Maths would give you a decent compliment of modulation sources on which you could use the comparator(s) to fire gates when the modulation curves pass given voltage points. Put this together with some logic to work with the Varigate, and you'll have lots of rhythmic mayhem possibilities.
Thank you very much Lugia for taking the time to provide, from the beginning of this thread, all your detailed and expert advices.
You convinced me about Maths, and I adopted your suggestions about the A-140-2, the comparator (I was totally unaware of that kind of module), and a logic to work with the Varigate.
All your comments have been a valuable input for me in this phase of discovery and understanding. I'm not completely a newbie in synthesizers (I began with an Arp Axxe in the 70's...) but the modular word is a lot different, and there are so many devices and options.
So thanks again.
A last question if it doesn't bother you. I already bought the RackBrute but I'am planning to order the modules in two steps for reasons of budget. If you have any suggestion, two lists, it will be very welcome.