TL;DR. Great proposal. I vote for 10% allocation to start.
I would quibble with the word 'excess'. We don't have an 'excess' of RFV and I don't think we should ever think of the Treasury as containing an excess. The Treasury is what it is, and we should manage it holistically as we would any portfolio- with specific risk and return objectives. I think this framing is important for effective long-term management.
With that in mind, I suggest we start very small, say 10% allocation of the Treasury to AAVE. It would be an easy position to scale up if things are going well, so there's no need to move into AAVE in a big way, particularly if better long-term, low-vol investment options begin to emerge.
I think once this proposal is implemented it will continue to spark more proposals for discussion around enhanced Treasury management.
For example, since they recently passed their code audit and have emerged from Alpha, I would advocate for a very small allocation of Treasury DAI (<1% or <$100K, whatever is smaller) to Orion Money (https://orion.money), which is currently yielding 12% via AnchorProtocol paid in UST and swapped 'under-the-hood' back to DAI on demand. As Orion solidifies and deposit caps are raised, we can scale up this position slowly, if the Community Agrees.