I think another issue is
-Is it really possible to coordinate such a large team to assess and vote on all the proposals without making it quite cumbersome. There are weeks without proposals but there are also weeks that have several proposals and I afraid in practice, there will be some TAB members who are more active than others and yet discouraged because they all get the same budget regardless of whether they are active or not.
I suggest it to make it individually rather than collectively and also compensation to be based on their individual contribution rather than collective.