1) I notice some apparent variation in sensitivity from band to band. Is
this normal, or am I looking at the possibility of leaky caps inside of
the RF compartments? (If the latter, I may just let this be for now. I
don't relish the idea of trying to get those rf boxes out of the set!)

2) Tracking is a little bit off as far as dial calibration, despite
repeated attempts at alignment. I wouldn't expect digital frequency
display accuracy, but is this typical of this set?
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Pete:

Some variation in sensitivity from band-to-band is to be expected, but
some of it may be a alignment/tracking problem. All the BC-348
versions I have worked on have a dial calibration error in excess of
the specs. The RF and Oscillator coils have trimmers to adjust the
high-frequency end of the bands, but only the LF band has a
low-frequency adjustable padder. The padder capacitors for the
high-frequency bands are fixed micas. The coil forms and perhaps the
micas have aged over the last 60+ years and caused the low-end
calibration to be off. There are a lot of small mica capacitors inside
the "coil cans" and many of them are non-standard values. It is
probably not a good idea to mess with them. I "fudged" the coils on my
BC-348-R and got the low-end calibration on spec, but it is a slow,
painful process. But, once done, the alignment has stayed put for the
last 5 years or so. It is one of my favorite receivers.

The size of a crystal is a function of frequency and the mode of
vibration. The BC-348 crystal is a thickness mode crystal is much
larger than a tuning-fork type crystal used at 32kHz. There is some
loss in the crystal filter, but not much. Sometimes the extra
selectivity reduces the sidebands to the point that the sensitivity
seems to be reduced, but the carrier remains strong. I assume you
aligned the IF at the actual Xtal frequency.

Running your BC-348 on something around 200 - 220 VDC should be OK. I
wouldn't go above 220. There would be no advantage to that. Putting
the power supply inside the cabinet of the receiver will raise the
temperature a good bit and raising the B+ above 220 will raise the temp
even more. I always recommend an external power supply. Put it in the
speaker cabinet. Your BC-348 will be a lot happier that way and more
stable too.

Best Regards, Ed