求教一下这个句子怎么翻译？

Snowdreams

Whilst appendages are a comparatively small factor in the displacement calculation, it can be important where the deadweight is small and margins are tight to have a good approximation for these items, at least in the later stages when the design is being refined.
If this can be done easily, there seems every reason to use the same approximations in the preliminary design stage.

这是上下关联的两句话，大意可以理解，但是翻译时总是十分别扭，求教大神怎么翻译？

Clockwork

等高手翻译。