I have now access to my 8-core computer, and worked during the weekend on 8x8 BT Draughts.
To generate the 12P DB took 3.7 hours.
I plaid 1 game (with 32 ply search) and the win (for white) was observed after 7 moves (black to play, so 14 ply).
This would indicate a 46 ply search from the start.
I started a (unfortunately) single thread search, as I did not implement the BT parallel search yet.
After 12.5 hour the program reached 41 ply (based upon above it should be 46 ply), but still with no win/loss score.
So work to do, I might need go to 13P DB (or further as Rein predicted) , and/or use a parallel search.....
Nice to see some progress. Could you post some search logs and end-of-PV positions after each iteration? What kind of eval are you using?
As I wrote before, the checkers solution had something like 62 ply, and with checkers men can't capture backwards, so a breakthrough is a lot easier to force:
With checkers, white can simply walk through here with h6-g7. With Brazilian draughts (international rules on 8x8 board), it's not possible as black can capture backwards f6xe8. So I expect that Brazilian draughts cannot be solved within 62 moves, perhaps in many more moves. For 10x10, I would be very surprised if it would take less than a 100 ply search to force the win without databases. Of course, databases will speed this up enormously, so hopefully you are very close already. Who knows
BTW, you can download Martin Fierz's Checkerboard + Cake + Kingscourt opening book to replay his solution: http://www.fierz.ch/download.php