Fitting Belt Type Bath Lift To Wood Floor

[Marantz]

I need advice please regarding fixing the floor bracket, the belt is drawn across the bath then down the outside to the floor where it clips into the floor bracket.
The floor is wood floor boards the bracket has 7 m6 size fixing holes I am thinking of placing a timber baton under the boards and fixing through to that.
My question is what fixings to use, rawlbolt ? or are there some other wood fasteners more suitable bearing in mind the lift will be supporting a person of 14 stone.

 

[Tigercubrider]

Not sure if 7 x M6 bolts through a floorboard and baton would not either pull the floorboard up or other wise damage the baton?
If you can get access under the boards then steel angle brackets fixed to the joist sides and level with the joist top might allow fixing through the timber and into the metal.
That way the load would transfer to the joists.
https://www.screwfix.com/p/sabrefix-heavy-duty-angle-brackets-galvanised-60-x-50mm-10-pack/61576