An interesting postscript to this.
I've recently been doing some approval work on a similarly configured aircraft fitted originally with a Rotax 912 engine, but in this instance fitted with the 2.2litre Jabiru - the same engine as is fitted to the Jabiru aircraft.
In that aircraft Vso was previously 34kn, whilst the recommended approach speed was 55kn (1.6Vso).
The 912 idles at about 1000 rpm, and has an integral gearbox at 2.27 ratio. This means that idle PROPELLER RPM is around 440.
The Jabiru also idles at about 1000rpm but is direct drive, so the propeller idle RPM is still about 1000. The result was a fair bit of residual thrust at flight-idle which wasn't there with the Rotax engine.
The effect of this was to reduce Vso to about 31 kn, and the TP (not me, I just did the analysis - but the same chap who flew the performance testing on the 912 version so handling techniques should be pretty much the same) found that if he approached at the original 55kn it floated forever. So, he took the decision to reduce it to about 47kn - which even compared to the lower stalling speed was now giving about 1.5Vs. Despite that, we still got a marked (+30%) increase in total landing distance - which was pretty much inavoidable since any further reduction in approach speed gave an unacceptable loss of control authority.
G
N.B. All speeds CAS.