using ADC complete to control PWM of LED

Using a standalone ATmega328p. I want to have the ADC to be triggered each time TIMER1’s COMPARE B value is reached. When the ADC is done, I want to use an interrupt to grab the data and to set an LED on PORTD to OFF. Then, using Timer1’s COMPARE A interrupt, I want to set the LED PORTD to ON. By manipulating the OCR1A value I hope to control the PWM of the LED. I am putting TIMER1 in CTC mode with ICR1 setting the TOP value. Does this approach sound reasonable? Here is the code I have so far. It appears to do what I want although I am not using the ADC output yet.

#include <avr/pgmspace.h>
#include <avr/interrupt.h>

void setup() {

  PRR |= (1<<PRTWI)|(1<<PRTIM0)|(1<<PRTIM2)|(1<<PRSPI)|(1<<PRUSART0); 
  DDRB = 0xFC;
  DDRD = 0xFF;
  DDRC = 0x3E;
  cli();          // disable global interrupts to allow for a clean initial state
  //*************  Set Modes
  TCCR1A = 0;     
  TCCR1B =0; 
  OCR1B =0;
  OCR1A = 0;
  // **************

  TCNT1 =0; // Wise to force the count in range
  ICR1 = 300; // output compare register used for timer1 A compare
  OCR1A=50;
  OCR1B = 0;  // everytime COMPARE match B, ADC auto triggers
  // ctc, IR1 sets top
  TCCR1B |= (1 << WGM12)|(1<<WGM13);
  TCCR1B &= ~(1<<CS12)&~(1<<CS10);
  TCCR1B |= (1<<CS11);
  TIMSK1 |= (1<<OCIE1A)|(1<<OCIE1B); // Timer/Counter1 Interrupt Mask Register
  // set up sampling of analog pin 0
  // ADEN: Enable ADC
  // ADATE Auto Triggering of the ADC is enabled. The ADC will start
  // a conversion on a positive edge of the selected trigger signal.
  // ADIE ADC conversion complete interrupt enable
  ADCSRA |= (1 << ADEN)|(1<<ADATE)|(1<<ADIE);
  //set reference voltage
  ADMUX &= ~(1 << REFS0) & ~(1 << REFS1);
  // Right adjust for reading 10 bit value
  ADMUX &= ~(1<<ADLAR);
  // 0000 selects ADC0 channel
  ADCSRA &= ~(1<<ADPS2);
  ADCSRA |= (1<<ADPS1)|(1<<ADPS0);
  ADMUX &= ~(1<<MUX3) & ~(1<<MUX2) & ~(1<<MUX1) & ~(1<<MUX0);

  // auto trigger on compare match B.
  ADCSRB |= (1 << ADTS2)|(1 << ADTS0);
  sei(); //enable interrupts
  ADCSRA |=(1<<ADSC);  // must start first conversion
}

ISR(TIMER1_COMPA_vect) {
  PORTD=0b11111110;
}

ISR(ADC_vect) {
  PORTD=0b11111111;
}

void loop() {
  // here I will manipulate OCR1A to change the PWM of the LED on PORTD bit 0
}

Seems like overkill. Brightness changing at more than 30Hz rate will not be noticeable to the human eye. Is there another use in mind? I think I would just use blink without delay, every 5mS sample the input with analogRead, shift it right 2 bits to convert to 8 bi,t, and analogWrite it.