If you need smaller increments than 2.5 lbs., go over to the "Training" forum on this site and find the thread titled "2017 Microplates for Sale" and buy those plates.
Don't focus on low numbers; focus on progress. You are strength training to get stronger. If you do the program, you will make progress.
I rest until I'm no longer fatigued. That's about 4-5 minutes during the worksets.
About my diet, maybe I slip below 2500 calories some days. Should I go 2500 cal everyday, or even more? I've no idea how much I should eat to improve at my height and weight, in the book Rip recommends anywhere between 2500-5000 calories which is quite a wide range to choose from. It didn't cross my mind that my weak bench is a diet issue though since I'm not having too many problems with the other lifts.
BTW I can't buy microplates online since I'm based outside of the US. Shipping plus import taxes makes it prohibitively expensive to buy fractional plates from Amazon, plus they take a long time to arrive (2 months+) and I can't sit on my ass for so long waiting for the plates before resuming with the bench. I think the "ghetto" microplates consisting of chains with a zip tie solve this problem though.
I'm just worried about my bench being so weak compared to the rest of my lifts, so early into the program. I won't lie, I want my upper body to be strong proportionally with my lower body, which doesn't seem like it's going to happen when my bench is less than half of what I can squat.
Squatting uses way more muscle than pressing does, don't worry about the ratio between them, just worry about good technique and making steady progress.
get some 2 inch flat washers from an industrial hardware place,
I don't know how many mini meters that is,
my 2 inch flats weigh 5/8 pound a piece, so a pair is 1 1/4#,
Stop worrying about nonsense like this. Start worrying about how to get some fractional weights (that are accurate) so you can actually train your bench press. I selected weights that were too high for my bench when I started as well. I tried to do 95lbs, I missed the last rep on the first set. I got it corrected as was able to make progress, like everyone else.
Which of these do you think is more likely to get your bench stronger?
A) Worrying about why your bench is weaker than the rest of your lifts so early in the program
B) Getting fractional plates, and getting a video of your bench, posting it in the forum here so you can get any technique issues fixed?
Just a rule of thumb I picked up from Rip that turned out to work pretty well...when deciding how much to rest between sets, rest until you're ready to do the next set, then rest 2 more minutes.
I'm suspecting a technique issue here. Put up a vid of your bench press...we can try to get it ironed out.