Anyone converted a driver’s license (外免切替) at Konosu (Saitama)? Looking for tips + instructor/school

Hi everyone,
I’m planning to convert my foreign driver’s license (外免切替 / gaimen kirikae) in Saitama, likely at the Saitama Driver’s License Center in Konosu.

If you’ve done the process there, could you share:

• Any common reasons people get rejected at the document stage?
• For the practical test at Konosu: what mistakes are most commonly failed (observation checks, signals, lane positioning, stops, etc.)?
• Any recommended driving schools or private instructors around Saitama/Konosu that specifically train for the gaimen kirikae practical test (not beginner driving lessons)?
• If you know an instructor who can help in English, please share how to contact them or what keywords to search.

Thanks in advance.