Hey Syd,
You may want to move this to the warbird forum for a better response.

Til then I will add my inflation adjusted two cents.

I prefer spring down units when use air retracts for the fact that should you develop a leak or expend your air supply, the gear will come down and lock.
Units that use air both ways require a larger volume air reservoir and give you no certainty of a down and locked condition when the air charge gets low.

But in the end Lados are my favorite!