You should probably test where are you currently. From the looks of it, you might have lost a good 30 pounds of strength. I would suggest starting 20 pounds lighter, and if you feel it's too light, add in 5s, till you feel like you have trouble lifting that weight 5 times. That should be your new max. To know how long you should bulk for we need to know what are your goals and your current stats in height and weight.
Adapting to what you want doesn't seem very strength oriented to me. It kinda sounds like you want some muscle hypertrophy. SL is a good muscle builder but doesn't give results as fast as a hypertrophy routine. Hypertrophy routine is pretty much doing basic barbell workouts in sets of 8-12, instead of 5, like SS. If you want to look your best in 4 months, then probably a hypertrophy routine won't be as beneficial though. That means you would have to bulk and cut in a period 120 days, which I don't see you gaining much muscle from 2-3 months alone so that you look big. If you say your pecs feel a bit soggy, but it's not really something that is fixed by doing pecs specific exercises. You did gain some weight, and that aids your pecs in being different from before. Bench pressing at your max will probably get your pecs rock hard again, trust me, I wouldn't worry too much about this.
How you should be eating during the bulk, I don't think there is much science to it. It's all about the calories. Remember, calories are calories, it doesn't matter if you get them from eating a California burrito with a beer or a apple slice, it will make the difference between cutting and bulking. For bulking, you should be trying to eat as much as you can. 2 bowls of cereal in the morning, and extra plate for dinner. Milk is your friend when bulking, try to drink a pint every other time. Peanut butter is also great during the bulk. Eat cookies with peanut butter, put peanut butter in your protein shakes. Put peanut butter in your cereal. Get that peanut butter in. Eggs too. Sunnyside or hardboiled, they are good for bulking. You can put 2 raw eggs in your protein shake as well, and no, you won't get an eggy taste. You will hardly notice it. Calorie dense foods would include bread, rice, and beans, avocado. You can never, ever go wrong with rice and beans. It's a really south thing, but give it a try. Red beans with white rice mixed is amazing, and an amazing calorie food as well, and has a great amount of protein. You should really be getting calories in. For short, eat more.
Working out at night is fine, just make sure you lift.
By the way, you have friends irl that use SS, but really, the extra 10 reps for each aren't doing much. You are building strength, so pushing those 5 in a row should be slow with perfect technique. I do 3x5 and seen better results from 5x5, because I focus more on doing 15 reps right. It also gives me time to push in some dips or barbell rows.
