The newer engines with long transfer tunnels looping towards the front work a bit differently (say on a Husky strato). It appears the engineers have actually designed the engines to utilise less blowdown so that the transfer tunnels get a big hit of exhaust gas down the tunnels. When you pull the jug, you can see the carbon from the exhaust going down almost to the crankcase.
It appears what they have done by using the long tunnels is to capture the exhaust gas to use in the loop-scavenging. With a conventional two-stroke, when the transfers first start to flow there is considerable turbulence and mixing of the mixture coming out of the transfer port with the residual exhaust gas in the cylinder. It takes a while for the 'freight train' of mixture to get established in a flow. The result is that there can be some 'short-circuiting' and dilution of the mixture.
By using the captured exhaust gas in the tunnels, they don't have to worry about turbulence and mixing - it is just exhaust gas mixing with exhaust gas. When the flow gets established, then the air from the strato can enter the flow and finally the fuel mixture from the intake port.