Welcome to the forum. Off topic: If you try to get into chat, it won’t work for you because of your username.
Don’t let a low LOT persuade you that your gains are likely to be minimal, just use your LOT as a guide for which way to pull to effect what, below 7:30 and you are hitting the ligs full on, and as someone new to PE you may see some good gains there. Try incorporating BTC stretches into the newbie routine to emphasise the initial attack on the ligs.
There is no way to predict gains as such, it’s a very individual thing and it will be effected by a whole host of factors (tissue strength, force over time, consistency of routine etc.).
If after 2 months on the newbie routine you are not gaining then switch your attack to the tunica but give it that 2 month chance first and don’t let the idea that you may be a hard gainer encourage you to overdo your routine.