Seriously, check out the forums on thehotpepper. That place has a LOT of information. Really helped
I got a cheap little electronic thermometer that works like a charm. Instant, accurate results. The pH meter that I got was this one from Apera:
https://www.amazon.com/Apera-Instruments-Waterproof-Tester-Accuracy/dp/B08FBY5SDL
It’s perfect and you’ll be able to open up to testing all sorts of recipe ideas and know that they’re def safe.
Since you’re doing vinegar based yeah as long as you are cooking the peppers and other ingredients in the vinegar you’re almost certainly fine. Mine is is a hab sauce with cider vinegar, fresh charred mango and fresh juice from lemon, lime, orange, and grapefruit and it comes out around 3.1. Knowing exact numbers will help if you ever decide you want to sell it. There’s a lot that goes into process certifications and you will 100% need to know a lot of exact pH’s for each ingredient you use. Thanks for the chat btw I love talking about this stuff.