Use SigHashDefault instead of SigHashAll in weight estimations.
Actual code uses SigHashDefault, not SigHashAll. SigHashAll is 1wu larger.
Use the actual destination address in weight estimator, not taproot always.
In the test the type of address is P2WPKH, not taproot.
Updated testSweepFetcher to calculate fee, fee rate and weight accurately and
to compare the data observed in the published transaction with the estimates.
If custom fee rates are used, the algorithm is tried. It selects a batch for the
sweep using the greedy algorithm, which minimizes costs, and adds the sweep to
the batch. If it fails, old algorithm is used, trying to add to any batch, or
starting a new batch.
Boris Nagaev