sistine chapel tour for three adults

What sources have you looked at? Have you looked at Walks of Italy?

There are 3 adult tickets available on the Vatican museum's website for the "Guided Tours for Individuals - Vatican Gardens and Sistine Chapel" tour in English for Sept. 3. It starts at 9:30 AM and lasts abt. 3 hours. Total cost for the 3 of you would be € 135.00. Tour description:

"The tour follows an itinerary which includes: the Vatican Gardens, the Gallery of the Candelabras, the Gallery of the Geographical Maps, the Gallery of the Tapestries (Renaissance art) and the Sistine Chapel. Meeting point: On the day of the visit go to the entrance of the Vatican Museums - situated in Viale Vaticano – and show the booking voucher (electronic format allowed) to the Security Staff at the entrance (15 minutes before the scheduled time). After passing through security, proceed to the Guided Tours Desk to collect tickets and to meet the guide."

https://tickets.museivaticani.va/home/fromtag/3/1725339600000/VG-Musei

Usually guides are not allowed to speak in the chapel. If that is the case with this tour, you could all download Rick's free audioguide to your devices for narration. The guided route of the tour misses Pio Clementino Museum, the Gallery of the Tapestries (Renaissance art), and the Raphael Rooms which are often included in other tours but it's possible you could 'fight your way back upstream' to see them after the guide leaves you in the chapel. Not sure about that, and you might be done after 3 hours anyway.

https://www.ricksteves.com/watch-read-listen/audio/audio-tours/italy

I've not taken this tour but it's one way to get all 3 of you inside for a reasonable price if your main reason for going is the Sistine so....?

Editing to add: I know you said you had the afternoon available, not the morning, so this probably doesn't work but I'm throwing it in just in case you can skip the AM activity. BTW, the Vatican doesn't offer any sort of tour JUST for the Sistine.

To add: if you must have a tour later in day, look at offerings from these tour companies:

https://www.througheternity.com/en/vatican-tours/#

https://www.walksofitaly.com/vatican-tours/?gad_source=1&gclid=EAIaIQobChMIs9-qzfWPhwMVRhKtBh2EAQK0EAAYASAAEgIPi_D_BwE&gclsrc=aw.ds

https://thetourguy.com/tours/vatican?_gl=1*3dgafv*_up*MQ..&gclid=EAIaIQobChMIv5yio8KShwMV9A-tBh2SkwUgEAAYASAAEgIhYvD_BwE

Others may be able to offer other companies or private guides - which are normally very expensive but can offer comprehensive narration - they've used.

Thank you all… I was able to find tickets on the day of our arrival Saturday… at 4:00 pm… our Rick Steve’s tour starts Sunday so although we may be a bit groggy from travel from the states we will be able to see this magnificent site!

I was able to find tickets on the day of our arrival Saturday… at
4:00 pm

Ah. Good that you were able to land some tickets but a word of caution? Tickets/tours purchased from the Vatican's own website are nonrefundable in every case. Most tickets/tours from outside companies have refund policies only with cancellation of 24 hours or more in advance. You need to check what the fine print is for the tickets you purchased. It's usually advised not to pre-buy tickets/tours for arrival days as any number of flight cancellations or delays or even baggage snags can result in inability to make the mandated ticket/tour time.

I completely understand that your opportunities to see the museums/chapels are limited so I hope all goes well! It's just worth mention that should all NOT go well, you'll likely be out the $$ unless able to cancel within the required time frame, assuming there is a cancellation policy at all, OK?

This will be a taxing experience in a jet-lagged state in a hot, noisy, overcrowded museum but you already know that, eh? :O)