I can understand the thinking behind scaling down in summer, with clear water, high visibility and bright conditions, a large hook and heavy hooklink may be a bit too obvious! My concern would be the higher chances of a lighter trace spinning in the tide and tangle. When using 15lb amnesia, reeling in a sea ravaged bait, I have had traces spin and get terrible line twist. At least with amnesia, you can stretch and straighten these twists usually. The 30lb amnesia doesn’t twist up anywhere near as badly. When scratching in summer, fining down may increase bites, but rather than fine the gear down, I keep my 30lb clear amnesia traces and size 1 hooks on my 2 hook clipped down rigs for “general fishing” and 2/0-3/0 hooks on running traces or pulley pennel rigs for bass etc. I try to aim to fish tides at dawn or dusk or even night, where the lower light levels help negate the concerns of visibility somewhat. I try to avoid going too small in case I hook something bigger or with a bit of a fight in it as they could “spring out” or straighten leading to a loss. Unless I’m specifically targeting species such as soles with small baits, then I may use a size 2 or even a 4, if I was missing bites, but if I’m honest, I’ll probably stick to a size 1! This applies to bait fishing using ledgering tactics, using grippers/plain leads etc. I don’t tend to float fish etc as this tactic doesn’t suit my marks 95% of the time. So I couldn’t comment on these tactics.
