Building PedalSHIELD MEGA, Seamlessly

Hello there,

I found pedalshield mega more interesting than the others as many of you probably know only because of OLED display. You can literally see what happens, what amount you're choosing, ...

I'm planning to create my own, entirely on one printed circuit board (as arduino is an open source kit and schematics are all around and super simple) instead of two stage PedalSHIELD board + Arduino main header/module. OMG i'm so impatient to route this thing out. Think about plexy glass enclosure which everyone can see that beautiful ciruitry. BUT i have some questions from Ray:

Sir,
Why Atmega2560?
This thing is kinda expensive in my region. This chip simply is the Atmel's highest technology and according to the code you're using just timers and huge heap-stack ram.

Does it worth it?
It depends a lot to me, but if anybody has done it before and have advises for me, All welcomes here

i just started to add components yesterday

Thanks. No, i got used to route tracks like it's a HF device, no more lack of free space; but hey! You mean that 28 pin amega328p used in Arduino nano? Am i get it right? THAT suppose to do spectrum analyzing for me on PedalSHIELD MEGA?

Ray escribió: I was talking about the ATMEGA328P-PU that is in the UNO, you can also do FFt with it.

This chip is used in various types of arduino evaluate boards such as UNO and also NANO . DIP and SMT packages are not scientifically different as i know. Am i wrong?

If it's true one question remains: Why Atmega2560? when you can run the entire project on a smaller microcontroller?
(btw i dont know how much flash memory requires (FFT + distortion + fuzz + delay + bitcrush + octaver))

For those who get to this topic now, forget about replies above. The whole idea of this project is to design a PCB merging arduino free extensive board schematic with PedalSHIELD itself. A quit pro-hobby for qualified nerdies. The only problem is the microcontroller. The mothership...

Here is a quick comparative table

Atmega2560	Atmega328
256KB Flash	32KB Flash
8672B SRAM	2272B SRAM
4KB EEPROM	1KB EEPROM
1 ADC	1 ADC
Analogue comparator	Analogue comparator
TWI	TWI
SPI	SPI
6 Timers	3 Timers (All PWM supported)
4 USART	1 USART
11 I/O Ports	3 I/O Ports
No DIP, 120pin TQFP	28pins DIP, 32pins TQFP

Will it run properly? Lower SRAM cause stack overflow? I just want this program to use. If any experienced person can help me to measure SRAM to use latter microcontroller instead of mega2560. There are too many unused pins! Expensive and ultra-rare to find in my region.

The miniaturized PCB turned to something you can see below