I need to know something!

Thanks everyone

@zeropol I did research before but I couldn't find anything

One quick hint for you though: Aerospikes have the least delta between their atmospheric performance and their vacuum performance. However they are also have worse TWR and max thrust compare to other nozzle types. So you have to decide if the stable performance characteristics are worth the power limitations. That said if I were designing an SSTO, and I weren't concerned about realism, I'd probably go with an Aerospike since we don't have to deal with some of the real world problems in SR2.

I suggest you do some research online. It is a lot more fun than just having someone tell you what engine you should use:
https://en.wikipedia.org/wiki/Rocket_engine
https://en.wikipedia.org/wiki/Liquid-propellant_rocket#Engine_cycles
https://en.wikipedia.org/wiki/Rocket_engine_nozzle
https://en.wikipedia.org/wiki/Aerospike_engine

Also "best" is dependent on a number of variables, chiefly the mass of your payload and your target altitude. A fuel type/power cycle combo that might be the most efficient for one payload/altitude wouldn't get another payload off the ground.

You can use the "performances" button to compare your settings influence on your craft.
There is a slider for altitude, and an other for speed.

Also, hovering the mouse on your engine settings ( in mobile, try long press instead ) brings you a sentence with clues about sea level/vacuum efficiency

I have no "sheet" for perfect settings, the fun in in the experiment and you'll find that you can dramatically improve your delta-V using the "performances" tools.

I have the simple engineer mod installed.
But I think the vanilla game already has the "performances" button. If not, try installing the mod.