A lot of the fun of owning Garrison has been converting figures and then producing the things. My last project was to produce some very Old School type Immortals, Medes and Persians in robes. The Immortal archer made it to the mould stage - I've even got 50 ready for painting - but the others have a far more uncertain future.
My normal method is to try and make several conversions of the figure I want. The worst of these - assuming they are useable - I paint up to see what they look like.
The unpainted ones were in the process of being put together for a mould when I acquired a load of their 'S' Range equivalents. With lots of figures to integrate into my current armies it's probable that development of these has now ended.
As to making the figures themselves, spearmen are simply the Garrison Persian officer with cloak and armour carved away. The sword has been replaced with a spear and head swaps give me Immortal and Mede variations. The Immortal archer is the top of 20PEC8, the Guard cavalry figure, on either the Immortal infantry or Assyrian infantry robed bottom half - I made both versions. Again, simple head swaps gave me the other figures.