You will normally get a 'rise and fall' with ferments; the mash/peppers will rise as the lacto expels CO2 (lifting the peppers) and then fall as the gas escapes. It's after the settling of ingredients that you'll know your ferment is close to being finished or ready to process.
When ferments are finished I normally do not add any vinegar when processing - the tang/acid is already there through fermentation. Nevertheless I understand/respect you wanting to be safe with your first attempt.
I use salt only (no starters) by weight of blended mash since I'm not using brine like you would with slices or chunks of peppers. Your question referred to brine though, and it is indeed correct at 1 tbsp salt per cup of brine. <-- That's a very strong brine though and you can easily reduce the salt percentage, especially if you use starters like whey or lacto capsules to help get it started. I refer back to
this page when looking for brine concentrations.
Your friend is correct that botulism can grow in an anaerobic environment but also keep in mind fermentation is one of the oldest and safest food preservation techniques known to man. Provided you are clean and safe there is little chance of you hurting yourself or others with fermented hot sauce - but remember you've got to be clean and safe. I remember I was very skeptical and afraid trying my first few batches of fermented hot sauce - made with knowledge gleaned primarily from here - and now it's become almost second nature. Some links of interest on botulism can be found
here and
here. Mostly that is a concern of low acid foods, while fermented hot sauce is quite high in acidity.
re: Wine for brine - I've never done it and can't offer anything.
re: fruit juice - I have used fruit juice in fermenting recipes with good results, though I tend to allow them more time to ferment. As a general rule most of my ferments run for 3-4 weeks and then go into the fridge unless I plan on bottling, at which point I will cook down and process/hot fill/hold. Ferments with more sugars can run much longer - up to 60 days or longer.
re: potato - this is a cooking trick I've seen used with success before in soups and stews. I credit Rocketman for popularizing it on THP and it does indeed work. To wit; IF your sauce is too saltly, add a peeled potato to the sauce while it simmers. By the time the potato is fork tender it will have leached out a good deal of salt from the sauce. Remove the potato (make hash!) and then proceed with your processing as normal.
If you've already read the fermenting 101 thread I would suggest searching and reading up on posts by Rocketman and Chili Monsta. Both are incredibly knowledgeable and have been kind enough to share their own tips and tricks with the rest of this community. The cabbage leaf at the top trick that Old Salty mentions above was taken from Chili Monsta and is something I use on most ferments.
I also made an introductory to fermenting with step by step instruction/recipe post a while back, you can find it
here. Your first foray into fermentation was ambitious indeed; 30 reapers is quite the challenge for most taste buds.
Above all keep at it - fermentation is a game changer when it comes to hot sauce.
