Re: Really need advice on reel size...
I totally ignore reel makers line rating and go by balance and capacity. Bigger is almost always better than smaller. As I commented recently in the rod forum about how to balance a reel to a rod, I just put a Nautilus FWX 7/8 on my light weight ONE #5 for perfect balance. Many of the newer skeletal reel designs are very (too?) light and this "7/8" only weighs 4.1 oz.
Besides balance considerations, for saltwater applications an important feature is drag surface sweep area...the number of sq. inches of contact. The classic approach which still works great, is a big, wide slab of cork as in an Abel, Tibor, Islander draw-bar reel. A new design concept that has rapidly and appropriately gained traction is multiple stacked discs. Not only is there more than one drag surface but both sides of the usually carbon discs are employed so sweep are is expanded while maintaining a compact drag assembly. Hatch, Hardy Fortuna and Ultralite DD, Orvis Mirage and several more use such a design in low maintenance reels. Nautilus NV and Ross F1 are other contenders.
I have fished the ECHO3 #9 and it was a very fine rod bonefishing but I fished it with an exotic German Vosseler S which is not so readily available here.