To create characters that are more likely to be more competent at their occupational skills than those who studied the same skill as a hobby, each character assigns 8 occupational skills (which must be at a professional level of 60%) that they can flip-flop once per scene. The player can flip-flop as many times per scene as they choose, but only once in a scene on a particular skill. So a doctor with a Medicine of 63% can flip-flop a roll of 85 into 58 once during a scene, and then cannot flip-flop their Medicine skill again, but they can still flip-flop their other occupational skills (First Aid, Pharmacy, etc.) once during that scene. If the occupation has less than eight skills then the player can assign as many hobby skills as needed to bring it up to eight.
This is obviously based on Unknown Armies' obsession skill mechanic, where you can choose one skill to flip-flop. I set the number at 8 skills because that's how many skills are assigned to most of the occupations listed in the 6th edition CoC rulebook. I required that the skill be at 60% or higher so that players still have an incentive to place a proper amount of points into their occupational skills. For the math wonks, at 60% skill flip-flopping increases the chance to succeed to 83%, it increases at 70% skill to 90% chance, at 80% skill to 95% chance, and at 90% to 98% chance; so, it still rewards having a high amount in a professional skill (60-80) but doesn't require characters to be Nobel Prize winners and Olympic athletes with a bunch of 90% skills to be reasonably competent.
In the spirit of Insane Insight, this rule allows a character to become so obsessed with a task that they lose all focus on reality but become much more likely to succeed at the effort. A player can flip-flop the result of any skill roll in exchange for losing 1 Magic Point and risking 1D6 points of Sanity. If a character goes insane as the result of an Insane Effort roll, they become fixated on succeeding at the task for the duration of the insanity or until brought back to sanity through psychoanalysis, drugs, and other treatments. Insane Effort cannot be used on Sanity checks, and can only be used in situations where the character is likely to develop a fixation on the task.
I don't know how they plan to do Pulp Cthuhu, but this is the mechanic that I'd use to create that setting. It puts it in the hands of the players if they wish to trade high-competence for less Sanity, and seems like it would establish a mood where the characters are both good at what they do but are still falling down the SAN loss death spiral. The big problem I see with this rule are in the Magic Points. I like using MP because, in my experience as a player, they are so rarely used, and because it creates a resource pool to keep the option in check. In truth, it's the SAN loss that would probably keep this rule in check, as anyone who tries to use Insane Effort more than 4 times in a scene will go crazy. I might fiddle with the refresh rate of Magic Points, so that they return at the end of a session or an adventure rather than every 24 hours, but I'm not sure.
* Please note that I don't think this is really a problem of mechanics so much as perspective. A game where characters bumble around and often can't succeed at their skills is in keeping with the way Lovecraft often (but not always) presented his protagonists, and the classic rules fit for the classic game. I just think that CoC is big enough to encompass a greater variety of characters and stories than just the source material itself, and I like these options as house rules when the Keeper wants to try something different.