The guide recommendations and the spacing between each guide as suggested by Fuji in the diagrams below, would appear to be used for rod blanks (ranging between 5.5ft to 7.5ft) with standard line-class ratings that fall between 4-20lbs (e.g. 4-8lbs, 8-20lbs etc). These blanks would mostly likely be designed to cast lure weights that fall within standard weight classes ranging within 1/8-1oz (e.g. 1/8-1/2oz, 1/4-3/4oz etc).
Rod builders may opt to further reduce tip ring sizes primarily for the purposes of shedding additional weight to increase rod tip sensitivity (particularly for ultra-light weight class blanks), whilst to a lesser extent, for aesthetic purposes by creating or enhancing the desired tapered look of the blank.
Fuji offers a choice between their tried and tested (a) Y and L Series Guides and their latest (b) tangle free KL and KT Series guides paired with an F Series tip.
Common spinning reel seats used would include Fuji's VSS and IPS range of reel seats in size 16, along with their DPS series.