Blackacre, i did exactly this on my Jeanneau
43ds last year. The female pin that came with my passarelle required me to drill all the way through the teak on the bathing platform and through the fibreglass. It is all quite thick and extremely strong. It would have been better with some bolts but on my boat the access underneath is virtually impossible so i simply used some very stout screws. This is a good solution but a word of warning since yr very attracttive (!) female fitting would let water into the space underneath in rain or big following seas. Mine has a cap on it which is secured to the female fitting on a short tether. The way around this problem of water getting in would surely be to use a fitment similar to the pic shown by HankonTheWater. I might in fact add a fitting like this to my setup since the bathing platform is a bit low for some pontoons and sometimes i need a point a little higher.
The matter of the wheels getting jammed in the slots between the boarding on the pontoon is a very valid point but has a simple solution. Simply set the level with yr uphaul arrangement such that the wheels are about 6" (10cm) above the level of the pontoon. Once it has the weight of a person on the passarelle the wheels will them firmly rest on the pontoon for the few seconds that your weight is holding it down.
You do need some sort of uphaul arrangement, many people use the topping lift
with a spreader gadget that looks a bit like a coat-hanger. I use a pulley arrangement from my stern arch (which doubles up in taking the tender
when i am out at sea). In addition to this you need an adjustable line from each aft corner of your boat across to the passarelle bec otherwise it will swing uncontrollably and dunk yr crew/wife/partner (?) in the water. I found that instead of tieing this line to each corner of the boat (unsightly?) i have one of those quick release dinghy
spinlocks at each corner. Helps to make the fine adjustment in a flash.
You then need to figure out where to store yr passarelle when not in use. There is one model which folds up v compactly thanks to 3 hinges. I chose one with no hinges at all so i then sling it under the top rails of my transom arch underneath the solar panels
. If you have one hinge the other way of doing it is to fold it over the lifelines/stanchions and then secure it.
Best of luck