If it were me, I'd ditch the boost pedal and set internal trim pot to 470K, replace 8K B+ resistor with a 5K for a total of 10K to raise preamp voltages a little (might need to adjust loop a bit to compensate since it draws power from B+). Original amp's NFB is 82K on 8ohm tap, so set the NFB control somewhere around there. The Feel/Bleed control is set a bit too high compared to the original amp and other similar designs. 82K or 68K would be a little better and yield a tighter, clearer sound as you increase gain. And if you really want to put some icing on the cake, replace OT with a Merren or Marstran 50W JMP. All of these changes will give the amp more upper-mid snarl and character and a tighter, more angry response. If that's what you're after.