Ball python housing questions! help!

[gusanr14]

https://gyazo.com/c9e182bc5bf94cdd8e3aaf3dc2b7924c
Before asking question, I don't have a snake yet but have set up ready and tested, except for heat source.

Hello, first question is helped by the picture I drew above (bad picture).
So the black square represents the tub and red square represents the heat source. Number 1 is the heat pad and number 2 is the heat tape.
Which way is better for providing heat spot for ball python? Both are going to be about 1/3~ 1/4 of the tub, both supported by thermostat.
P.S, Making a rack that goes in side way like above, so long side is going to be the front and back for the rack.

Second question is going to be humidity. As of right now, I have 15 qt for baby ball python that I will be getting. In the future, I am going to change to a bigger tub.
My room humidity stays around 40%. However my 15 qt tub with water bowl stays around 70%~75% inside the tub. What is ideal humidity for ball python? above 70% seems to high so I am going to put more holes in the tub. I started off with few holes to control humidity.
For now, humidity doesn't seem to be a big problem because it doesn't get low. However if I change to a big tub later on, I don't think water bowl can't help a lot for humidity since it is going to be a bigger tub.
I know I can spray down the tub but what percentage does spraying bring up the humidity? I believe humidity is going to stay around 45~50 range with just water bowl, not too sure in the big tub.
All tubs I am referring to are sterlite plastic bin.

Lastly, about the temperature, I know hot zone should be around 90 and cool zone at 80. My question is, is it okay to be at 75 ? Of course, it is going to be my first time keeping snake so I don't know better but I feel like it could be 73~75 because even though ball python live in hot area, nights are going to get colder honestly. If I am wrong, correct me please haha. Thank you!

[tttaylorrr]

option #1 gives you more room to create a proper thermal gradient. go with option #1.

ideal humidity is ~60% and never allowing it to fall below 55%. 70% is okay during sheds. what type of substrate do you plan on using? not all substrates hold on to humidity, with coconut substrates being the best at it. for the smaller tub, use a dryer substrate like aspen, and a coconut husk substrate when you move to a bigger tub.

75° F is the absolute lowest temperature i'd ever be comfortable with. i try to keep my tubs near 80° F but this time of year makes that difficult.

[gusanr14]

I am planning to use paper towel.

[tttaylorrr]

I am planning to use paper towel.

that should be fine. add a couple more holes until the humidity gets into a more comfortable range.

[wolfy-hound]

I agree, #1 allows more of a temperature gradient.