Get the one small enough to fit in your bore with the mirror. Mine with mirror wouldn't fit in the bore, then mirror broke off when used. Actually, camera is good for the 25$ I paid. Software ( yawcam ) is OK but could be better. Freeware stuff on the net is pretty poor. Many vendors of it so choose carefully.
Make a pound cast if you want to "see" just the throat. Bonus: You can also measure what you see.
To answer your question, I got the 20-caliber one for Android and PC for $49. Het creative with eccentric bushings for calibers over .30. Only one kind of software worked for me on my phone, it's called "endoscope camera", got it from g**gle play. OTG was rated much higher but did not work. You have to give it all the access permissions it asks for or it won't work.