H1B dropbox with multiple I-797 petitions with the same employer

I have an I-797 (current) expiring in Sept 2023. For example, this month (March 2023) My employer will file for an extension (in premium process), and it will approve April first week, and it may be valid up to Sept 2026. My current H1B stamp was expired Sept 2018. I have some urgent work in India, so I am planning to go in April month, already booked the drop box appointment in Hyderabad consulate in April month. I have reviewed a lot of rules and procedures but did not find anything in writing regarding a couple of questions I have, for which I need help with and hence the request for counsel, advice, opinion etc.

While filling the DS-160 form, it only allows you to mention one H1B receipt number. While the general advice on forums is that one should use the latest I-797 (starting in Sept 2023, thus 5 months in future) receipt number. Most of the people has advised on using the current I-797 receipt number but submit both for the drop-box, which frankly sounds more logical to me. Has anyone been in this situation and what receipt number have they used? Any known issue with using the current I-797 receipt number? Results with using the current I-797?

I know it is technically possible that they can issue a visa only until Sept 2023 and ignore the latest I-797. Is it typical to ignore the new I-797 or do they generally honor the combined periods of I-797?

Is anyone aware of any limitations around minimum number of days remaining for issuing a H1B visa stamp? For e.g. is there a stipulation that says for an H1B visa stamp to be issued, you should have at least 180 remaining on your H1B I-797 approval etc.?

Thanks. I would greatly appreciate your input.

Ideally your DS-160 will refer the I-797 that is current on the day you appear for the interview/dropbox so in your case because your visa stamping will occur before your extended I-797 come in effect, refer current in DS-160 and submit both current and extended I-797 along with other supporting documents. CO are aware of the extension of status situations and should issue a 3 year visa.