Using the same reusable launch system for all payloads which lands without chutes.
Using old school engines.
Assembling a separate direct ascend vehicle without chutes which has ladders and extra space and carries a rover and later brings it back to kerbin.
Bring the crew in a transfer stage with extra space plus lander without chutes which later remotely returns to the transfer stage which then remotely returns to kerbin orbit and stays there, while the crew gets back in the separate ascend vehicle which land on kerbin without chutes too.
So everything including the rover and lander is reusable and returnees
And I think it gives:
On Tongues of Fire. Use no chutes; propulsive landings on both Duna and Kerbin. 10%decrease in highest payload mass.
Old School. No nukes or ions. 3% decrease in highest payload mass.
Brute Force. Assemble a Direct Ascent vehicle in LKO; no ISRU, no propellant transfer, no Duna orbit rendezvous. 12% decrease in highest payload mass.
Slow Climb. Put ladders on your vehicles so you don't have to jetpack around on the Duna surface. 4% decrease in highest payload mass.
Elon Style. Make the whole system fully reusable without using nukes, ions, or airbreathers. 25% decrease in highest payload mass.
Stayin' Alive. Bring extra living space (at least one extra seat per Kerbal) for the transfer to and from Duna. 18% decrease in highest payload mass.
Loop The Loop. Make your transfer vehicle a fully-reusable solution that can brake back into Kerbin orbit and be used again for the next trip. 15% decrease in highest payload mass.
Consistency, Good Sir. Make all of your launches with the exact same launch vehicle. 6% decrease in highest payload mass.
Justin Case. (NEW) Provide your crew with a separately-landed ascent vehicle as a reliable way to get off Duna (inspired by The Martian). 18% decrease in highest payload mass.
They See Me Rollin'. (NEW) Bring a rover for your crew to get around Duna. 15% decrease in highest payload mass.
Which is 126%?
Even if I exclude brute force, because parallel to the direct ascend vehicle there is a second ship, which docks to the transfer stage before it returns, it's still 114?