Ctx 6/17" coils

[Ground Inspector]

I have a couple questions regarding the 6" and 13x17" coils.
For a normal sized-coin target (dime-quarter), how much depth does the 6" coil lose in manual +3 sensitivity?
How much depth does the 17" coil gain?
Any input is greatly appreciated.
I currently have the 18" coil for an se pro.
I'm thinking about getting one or both of the coils mentioned above.

I tend to hunt at parks, churches, and courthouses. The coins are at natural grass-decay depth (6-10" for a pre 1910 coin). Some areas have high trash from torn down buildings on the same site. Some are fairly clean.

Thanks

 

[Bart@Big Boys Hobbies]

As every condition is different you can't nail down that answer. I have hit coins with the 6" at 7" with good tone. All depends on surroundings,

 

[Hosensack]

I did a purposeful test with the 17" in a grassy yard next to a creek. Uncles property previously unhunted, spent an entire day gridding it out with the stock coil, went back the next day with the 17" and pulled a few Pennies at 12". Both days was only clad but the stock was 8-10 with varied signal strength...granted this was great soil.

I can't help with depth on the 6", it helped me pull some smaller buttons out of a spot I've hit previously but they were all only 4-5" deep.