Codamedia, PierM and HonestOpinion,
Thanks very much for your responses, all very helpful. I am looking into the impedance issue. Impedance was set to 'first block' in Global Settings and to Auto for each patch. I have volume in the first block of all my patches, so that shouldn't be changing the impedance from patch to patch. Still, I will try setting the individual patch impedances to a fixed 1m and see if that changes anything.
I was able to get some trails to spillover convincingly, seems more pronounced with delays versus reverbs. Also, to clean up the transition I probably need to focus more on muting the strings before switching patches.
Appreciate your help !