Quick disconnects size choices

[jonsstihl]

I'm planning the plumbing for my remotes and have a few questions about quick disconnect sizes.

I'm going with a two spool valve for tnt with a quick disconnect on the pb port of the valve for a splitter. this qd set will be 1/2 inch to match the male qd ends all ready on the splitter but for the other qd's I don't know what size to go with. my tractor uses 3/8 hose so I will use that to plumb the valve but most people seem to use 1/4 hose for tnt. Is there a standard size for cat 1 qd's and can adapters be bought to convert from 1/4 inch hose to a 3/8 qd.

the valve I am going with is a prince sv with sae 8 ports.

 

[jonsstihl]

how do you tell what size a QD is?

if I have a 1/2 QD what part of it will measure 1/2 inch the tip of the male part or something else?

 

[6sunset6]

Here are some comments in random order.
Rule of thumb is QD should be one size bigger than the hose. There are many brands of QD and male and female match better if they are the same brand. Although there are standards Like ISO A and ISO B etc.
I use ISO A and I notice that 3/8 QD have 3/8 female pipe threads and 1/2 QD have 1/2 female pipe thread. I don't know about others but I would guess the same. All that said 7gpm on a 30 hp Tractor is probably average and a 3/8 QD will pass that no problem. MY FEL disconnects are 3/8 .
Most of the time I try to slow down the gpm. The exception being a spitter with a 4" diameter cylinder which will probably want as much flow as it can get. Another fact is flow restictors generate heat , oficies or small hose or QD. But tractor cylinder operartions are not continuous and so the heat disapates before it becomes critical.