Hi Derek the Diver,
It's a bit pity to use a VCA as a kind of pre-VCA for yet another VCA :-)
If you have a Make Noise - Maths or ModDemix you might be able to get it done with those as well, not sure, I haven't tested it myself but from the look and the quick read from the manual it looks like they should be able to help you out. The Maths Channel 2 should be taken if you consider the Maths, channel 3 has an offset of -/+5 V only while channel 2 can go up till -/+10 V.
Not sure if this helps and in case you seriously want to use a pre-VCA for a VCA and you consider to buy a new VCA for that, consider then the Waldorf - DVCA1, that's a fantastic and underestimated VCA, it can do linear or exponential or both, whatever you want and has an additional boost of up to +13.5 dB.
Good luck and kind regards, Garfield Modular.
For review reports of Eurorack modules, please refer to https://garfieldmodular.net/ for PDF formatted downloads