Backdoor Roth Question

Hi, I’m new to the forum and to investing. I received a promotion around a year ago and have been able to pay off all debt excluding mortgage in that time period. I am now focusing on investing and learning all I can. I am currently not eligible to contribute to a Roth due to income, but I still want to utilize. I have opened tIRA’s for myself and wife. I am maxing out my 401K, but wanted to get recommendations on the backdoor Roth. Should I contribute monthly to each tIRA and immediately roll to Roth each month or should I wait until I receive my bonus and do the same thing with each account? This might be irrelevant, but I wasn’t sure if it made sense to do this monthly. Any thoughts would be appreciated.

Thanks, CB