According to the Fox site, for my weight I should have 95 PSI of air in my (new – less than 1 month) Float R's.

At this setting I can coast along and using just the force of my weight, I can compress the works to 3/4 travel. This to me seems way too much.

So I tried increasing the pressure incrementally, until I hit 115 PSI, which felt much better.
Only trouble is after a couple of days the pressure seems to drop back to sub 90 PSI.

So, What pressures are similarly weighted (180 lbs) riders sticking in?
And does anyone 'lose' air?

Im no expert but if you find 115 psi works for you forget the book as its just a guide as for losing pressure, it shouldnt, check the valve first call.

You'll lose some pressure when you attach the pump. I set my forks to how I like them,not how the manual says.

Im 170 lbs and run my f100s at about 80psi. You only lose pressure when you attach the pump, so if you keep checking it'll go down.

I run my floats at 65psi and i weight 160pounds, i never feel them noticeably bottoming out, feel nice and plush

set them how you like them. Just see how much travel your getting during a ride on big hits if your not getting near to full travel your forks maybe too hard. There's no point having 140mm travel if you only use 90mm and the forks feel harsh on the trail.