What sampling rate should I use ?

Use the highest sampling rate available. The more samples the better ! The only reason to use 44.1 khz is for CD compatibility. The use of 32 khz is not advisable for any reason except a shortage of tape. If it comes down to record at 32 khz or don't record, then I would use 32 khz. The reason is not only lower fidelity, but machine compatibility. The tape runs slower, this makes it harder to track in another machine.