With much consultation from Gary DeBock and lots of advice from Steve Ratzlaff's recent testing and posts, I decided to try replacing my LW 7.5" "G" Type 33 Loopstick 1700 uH which is optimized for Longwave, with a new Type 61 7.5" Mediumwave Loopstick.
I used the bigger 100/44 Litz wire and was aiming for 550 uH Inductance. It took 75 Turns of 100/44 Litz which measured anywhere between 530 to 550 uH on the DM 4070 LCR Meter. (The DM 4070 LCR Meter seems to be a bit erratic at times but it eventually seems to settle out).
Results so far after a day of testing have been amazing! The Top End of the MW Band has been completely opened up. I have even been able to receive 2 - 1000 watt Stations @ 1670 kHz - WTDY Madison, Wisconsin / 600 Miles distance, and @ 1700 kHz KBGG Des Moines Iowa USA / 600 miles distance as well. The Station at 1700 was received on the PL 380 with a Signal to Noise Ratio as high as 10 but it quickly faded out, guess since its only 1000 watts at night & 10,000 watts during the day. I have been receiving a tremendous boost to almost all Stations right across the MW Band and late last night I picked up KKOB 770 kHz in Albuquerque, new Mexico 1815 Kilometers distance (1128 miles) which is not too far from Mexico, and I am in Canada.
The best part is the I can still get many Longwave Beacons starting at 202 kHz with the help of my Longwave Coupler, and at about 287 kHz with the PL 380 itself.
These tests again definately verify Steve's and Gary's testing and have provided some amazing MW DX Results from here in Canada in that with a 7.7 Inch Loopstick designed for approx 530 to 550 uH Inductance the PL 380 is definately capable of receiving the entire MW and a good portion of the LW Band. Hope this helps others building one of these excellent 7.5 Inch Loopsticks.
I have posted a Picture in the Photos Section and will try to add a photo here if possible of this new type 61 Ferrite Rod 7.5 Inch Loopstick.