I just got home from a great weekend of detecting. 6 hours straight on Saturday and 7 hours today and zero issues with my LRP, bluetooth transmitter or headphones. I never take the headphones off when pinpointing or chatting with hunting buddies. I will say watching my buds fight their AT Pros headphone cables can be amusing at times, painful too as they drag their machines across the ground.
Ok the tones as stated before on Disc 4 (which I always run, disc=19 v-break=29) Low/Medium/High with VCO in the middle.
from the LRP manual...
"4-Tone Audio Target-ID
The detector will produce 1 of 4 sounds for any metal detected: V.C.O., low-tone,
medium-tone or high-tone. This audio feedback system is useful in conjunction
with the visual Target-ID system described above."
The hearing aid situation is tricky, some headphones could cause alot of feedback while wearing them over your hearing aids. Using just the speaker, you may just hear wind or environment noise rather than your detector. My suggestion is to get the Taotronics bluetooth transmitter
http://amzn.com/B00P24XKS8 and what ever bluetooth headphones you are comfortable with. You may even pair a single earpiece for a phone so you could keep one hearing aid in. It is just finding what works for you best. I personally run the volume at 4/10 on the LRP and it has been perfectly clear. I can even hear the barely audible hum of the detector and know when it discriminates out iron because the hum goes away but no tone emitted. That has been very helpful when I though there was falsing.
As far as balance goes, the LRP and the 11" DD received 13 hours of swinging over the weekend. I discovered that I had the shaft extended too far and it was causing an ache in my shoulder after about 4-5 hours yesterday. I imagine that swinging any detector for 5 hours would make your shoulder ache, no matter the machine. I am looking forward to getting the 5" DD for those trashed out sites like I hunted Saturday but I managed a ring out of a giant cluster of pull tabs
Also there will be folks that say only get bluetooth 4.0 or it will have lag. This is only important on the headphones and not really for the transmitter as 3.0 and up is fine.
Hope this helps,
HH