I recommend documenting each withdrawal attempt with clear timestamps and saving all replies from support as they become the record you will need if a dispute arises. I did this across several operators and compared how long verifications and release of funds took from request to receipt. In parallel I read several forum threads to match my timeline with other users and that helped me weed out sites with inconsistent handling. One resource I used when I began compiling data was
Bwin which collected notes about processing times and verification steps. By combining my personal timing records with that kind of collected feedback I was able to rule out providers that had unpredictable delays and stick with those that processed small withdrawals reliably.