Hi Jeff,should have mentioned in the 1st post i also do have larger coils as well,3 infact i bought the 15'' T2 coil for a ultra stupid low price brand new from someone about 6 months back basicaly no one wanted those coils due to the weight so they sold them at what ever they could get for them,but as i would only use it with a harness and on specific sites the weight is not a issue.
I also have the SEF12x10 and even its bigger brother the SEF15x12 both these are pretty light but much deeper than the stock coil,the latter one with the right settings is the deepest VLF machine that i have ever used,you dont want to use that every day for sure but boy its like digging 'graves' its that deep.
This is why,i have never really wanted to upgrade,mine must also be a monday machine,alot of it is also in how you set the T2 up,as you have all ready mentioned 4-5 and 50 kick the boost into play and also by adjusting the freq shift either slightly up or down can also have just a slight improvement to performance.
Was planning on going out tomorrow but the weather looks pretty pants,so have been told some decorating is on the cards.