I am trying out the #2 idea (flip flop rolls) because I am trying to get away from math at the table as some players find the calculating 1/5 skill and 1/20 skill awkward. Not because I find the math hard but because just mentioning math puts some players off! Lol.
This is how I deal with different difficulties and with calculating criticals, specials and fumbles.
I like the 7e solution of showing the different skill percentages on the character sheet but when you start adding in and subtracting percentages, you have to recalculate the break points. My play test solution is entirely die based. Some of my other house playtest rules have prompted this. For example, in Superworld, I have defined, for my home games only, attacking in brawling (fists only) as always being an easy skill roll, as I want to encourage hand to hand to simulate the comics. All other attacks (using the projection skill) are average as usual.
Instead of doubling or halving skill percentages I have started testing the following: (I have a Monograph for Chaosium for BRP part written, but it has a number or changes to encourage heroic play).
Easy skill difficulty, roll % die, use lowest die as tens. If HtH combat skill is 50+, attacker can make one attack at easy or two attacks at average. (the logic is an easy skill roll of +50% gets doubled to over 100% and so allows two attacks). Combat skill of 75+ allows one attack at easy or 2 at average or 3 attacks at hard. Combat skill of 100+ gives one at easy, two at average or 4 at hard.
Average skill difficulty, roll %, use die as normal.
Hard skill difficulty, roll %, use highest die as tens.
A special result is scored if the skill is a success and there is a '1' showing on either die. That gives just about the right % based on 20% of original skill.
A critical result is scored if the skill is a success and there are doubles on the dice (11, 22, 33, etc). This gives about the right % for criticals
A double 9 or double 0 is always a fumble and for some difficult-to-use weapons, possible double 7s and double 8s as long as 77 and 88 are not successful rolls. A high base skill reduces the chance of fumbling with difficult weapons.
E.g. Dodge is 63 %. Average roll of 41% is a special, roll of 55 is a critical dodge, roll of 71 is a failure (cannot flip dice on average skill difficulties). No working out of %s needed.
Hero A (brawling 40%) who has some advantage over villain B, punches the foul fiend. Hero has 40% + 30% (for advantage) gives 70% (two attacks this round due to advantage). Attacks once and rolls 83%, reverses dice and hits with a 38%. If hero A had taken two attacks, that first one would have been a miss.
I am not convinced yet that I have worked out the percentages correctly but it IS quick at the table.