For a 5 gal batch, I have used 14 pounds of strawberries for a very good strawberry flavor result even though I put it in the primary in a puree. I recomend for 7 gal you use 20 pounds and put it in the secondary, freeze thaw, blenderize and hit up with some pectin enzyme. Then you just simply put the resulting puree into a nylon mesh bag in a very big brew bucket, cover. After a month, Strain out the puree. Let it hand and drain a bit as you will get some water absorbtion of the fruit. Then let sit for a month more and rack. Rack every 2 monts until clear toping up water if neccessary or not. Doesn't matter. The result will take a little longer to age but it will smooth out wonderfully. If you taste it 6 months into the aging it will still taste green but you can tell the awesome potential. I recomend 14-16 months aging time when it is clear enough to bottle. And to be clear, Make very sure that there is no sediment and you can read newsprint through the mead prior to bottling. I find that strawberry is more difficult to get completely settled out. My recomendation, when you feel it's ready to bottle and age, wait at least one more month. You WILL end up with a jewel of a mead.