.025 x .190 seems like a decent starting point. I wouldn't use a TSR unless you can't get it to go cleanly from idle to off-idle and onto the mains. Work on the initial opening, IFR, and IAB first.
The transfer slot is a both an air bleed and a restriction. Restricting the fuel in is trimming of fuel that already has a air introduced into it. Its one way to deal with slots that are too long and certain idle low rpm engine characteristics.
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