14" Greenhorn wands start at 010 flow, with checkvalves it's probably closer to 09 net flow, but it's 1.5X more than most guys use.
We have just as many Greenhorns leave the door with 015 flow for customers with big trucks and or high heat.
And no you don't NEED 2.5" vac hose to run 015 flow, plenty of guys do it with 2" all the way, some even have 020 and report back no significant drying change except more one-pass cleaning and faster production.
Gary, with your White Magic unit you will have better consistant heat control if you increase your jet size, at least bump to 08 flow if it's a traditional PMF style wand with the jets pointed straight down at the carpet keep your pressure the same, if the wand has angled jets where the solution strikes at a forward angle towards the vac slot you can increase pressure about 100 psi with no issues.