Couple a things as I had a helluva time with my conversion. I swapped from manual to power though. Ensure your pedal isn’t pre-charging the booster having to do with pedal rod adjustment into the booster. There needs to be a bit of free play with the pedal in home position – not binding against the brake light switch. Had a ‘time’ putzing with this. The booster has to be of a compatible size for the setup. Though sounds like this isn't an issue. As well, the MC bore is different btw a power and manual setup. You likely know all this; just throwing out some things I remember with my conversion. Other thing here, is checking booster to MC gap.
As posted, there are three vac checks you can do on the booster with a pump vac gauge. Also I had issues with the rear brakes not an issue for you other than assuring the linings are adjusted (in my case the drums were maxed so had to get new ones).
Another thing I found is the pads were binding a bit, not backing off/sliding freely in the calipers, so did a better job deburring and lubing those..
