Hi Franky,
You should see a log.txt file in the optimization's output directory. In there you can find the mapping between backtest ids and parameters in the lines that look like these:
2021-07-28T22:55:50.2692799Z TRACE:: LeanOptimizer.LaunchLeanForParameterSet(OID 5b2353db-21e4-43e8-91be-2d82d925f2fa): launched backtest '71dc5085-4b29-4c71-bc37-e92527d38dbd' with parameters 'slow-period:50,fast-period:5'
2021-07-28T22:55:50.2712157Z TRACE:: LeanOptimizer.LaunchLeanForParameterSet(OID 5b2353db-21e4-43e8-91be-2d82d925f2fa): launched backtest '605449d7-8599-43b1-95f8-662041d58b40' with parameters 'slow-period:51,fast-period:5'
2021-07-28T22:55:50.2721825Z TRACE:: LeanOptimizer.LaunchLeanForParameterSet(OID 5b2353db-21e4-43e8-91be-2d82d925f2fa): launched backtest '5e323122-23fa-45d0-8703-0820f0eb10df' with parameters 'slow-period:52,fast-period:5'
2021-07-28T22:55:50.2732631Z TRACE:: LeanOptimizer.LaunchLeanForParameterSet(OID 5b2353db-21e4-43e8-91be-2d82d925f2fa): launched backtest '905ed00b-757d-441e-9aae-675242e2ab0f' with parameters 'slow-period:53,fast-period:5'
2021-07-28T22:55:50.2747383Z TRACE:: LeanOptimizer.LaunchLeanForParameterSet(OID 5b2353db-21e4-43e8-91be-2d82d925f2fa): launched backtest '304c20d0-9d1b-4774-a152-61f4f1018559' with parameters 'slow-period:54,fast-period:5'
2021-07-28T22:55:50.2760946Z TRACE:: LeanOptimizer.LaunchLeanForParameterSet(OID 5b2353db-21e4-43e8-91be-2d82d925f2fa): launched backtest '17ea0e25-b9ae-444d-ae94-5e0e569f2baa' with parameters 'slow-period:55,fast-period:5'