Thanks for all your replies.
Using your guidance and some work on my side, I got the simulations to work with a 20x speed-up compared to my previous Python Brian simulations, which is great!
The symmetry issue is not a big problem. After 500s of simulated time I see less than 10% deviation between two pairs of weights, which is OK for my needs.
E.
Shared (Symmetric) synaptic weights
Re: Shared (Symmetric) synaptic weights
That's great! Thanks for letting me know.