I hunted most all of my early Relic Hunting days with a Whites Spectrum SL and did quite well with it using a stock 9.5 inch coil and later using the after market Hot Head Coil which got me some extra depth. (I dug three ringers at depths similar to the pics in the post above with that old Hot Head Coil.) I also was using a Tesoro Toltec 80 and 100 in combination with my Whites which I will explain below. I still own the two Toltecs and use them regularly with great success.
I believe that the combination of the two types of Detectors was key to being as successful as I have been. I used the Spectrum first on all areas because I could hunt the area faster and it was really good at finding stuff at high speed. After I thought I had done a good job on an area with the Spectrum, I would then go back with my Tesoro and spend time with it going slower next to trees, in bushy areas, next to rocks and other obstacles. As you already know, the slow motion of the Tesoro allowed me to find things that were hidden next to obstacles and in trashy areas that I could not get that close to with the Whites. I often pulled small buttons, and bullets, etc., from tight places with the Tesoro. The Tesoro was good at looking into trashy areas and would often pull things out from between rusty nails, etc.
In conclusion, and I think most folks will agree, I believe that relic hunting is a lot like golf. You have to have different clubs for different shots to shoot a good score. With relic hunting, it has been my experience that multiple detectors with multiple coils was the only way to insure that I got everything that I could possibly get. I believe you will do well with a Whites for relic hunting with a mixture of coils but I would keep a slow or non-motion machine for close combat with trees and bushy areas not to mention trashy areas. Depth is a good thing now but don't forget that there are just as many targets hiding between trash and right next to trees, stumps and bushes too that you will miss if you are swinging a high speed machine through the woods!
I don't own a Whites anymore and have now acquired a Sovereign to add to my arsenal but only because I live here in Florida and I was looking for a good relic/beach machine. I am going to give it a good test this week by going back to one of my old civil war relic areas that I have personally covered hundreds of times to see what I can find if anything using all of the coils I have available to me at this time. The place was loaded before and I am sure there is some deeper stuff there.
Well I hope I have helped in some way but I believe you will be happy and successful with that Whites.
DaChief!
