To avoid the need to tune the loop while you tune the receiver you should use an untuned amplified loop like the one discussed in the thread
MLA-30 Active loop antenna for valve radios
I was very pleased with mine when used outside with a larger single turn loop, but I've just tried it indoors with 5 turns of thick copper wire, dia about 8 in. This gives good reception of the local and semi-local MW and LW stations, as well as all SW bands. You would need to experiment with a step-up ferrite transformer
Should fit in your radio, and you'd need to find somewhere around 12V DC for it