I tried to velcro in between the securing press studs, worked to a certain degree, didn't stop all the water thou

 Don't think there is a good way apart from avoiding the nose dive. 

Could try a need of silicone under the edge but I don't think it's a permanent fix

Mate you need to go to an ali manufacture and put a return on your windscreen so water dont run up it. You shouldnt be getting any water that high and that far back. Maybe go a little quicker.  

 if its pushing through zips then just rub some marine wax into the zip to stop the water sometimes if its coming through stitching surfboard wax can do it 

if its coming between window and clears if there just buttons then a bead of silicon can cause enough of a barrier to stop most of it but can look abit scrappy 

 I used to have a similar very late model Whitley sl22 that had exactly the same problem, I solved the problem by getting a Caribbean 235 crusader and have never looked back, 30 years older and 10x drier, hardly even get a drop on the screen as she does not dig into the next wave when it's rough. Good luck.

Buy the new boat, no one should have to put with that :-)

Buy, buy, buy! Or weld a big chunk of angle to the top of the screen  

I used this to stop dust ingress on an offroad camper trailer several years ago and it worked really well.

https://www.bunnings.com.au/raven-grey-rp59-window-and-door-weather-strip_p4061843

But after two "other" boats, I also own a Caribbean Reefrunner now 

 No, not the Reefrunner  ( although you know you want to)  . I had exactly the same problem with my Swiftcraft Dominator. Stick the bow under a big green one ( we fish some real crap up at Ningaloo, wouldn't do it at home.) and it would do as you say, run up the screen and drop onto the dash in large amounts. I did manage to fix this. The soft top was fixed to the top of the screen with studs. I had this changed to annexe track- the sort you thread a rope edge into. Fix the track to the top of the screen, have the press studs in the soft top done away with and  rope sewn in. Didn't cost me much, IIRC, just modified my existing one. Worth a try. You then have a barrier with no gaps for the entrire width of the screen. 

I have same issue on mine so I fitted some self adhesive foam between the buttons on the windscreen.

Doesn't block everything but cuts down on the amount coming in.

Also glued some clear plastic (thinner than the clears) on the outside of the zip openings. Can still roll up the window etc. Once its wet it sticks itself to the clears, covering the zips.
Again not perfect but better than before.. and cheaper than replacing the clears.

But you know you need the Reef Runner ;)

a bead of black sicko between canvas and windscreen. Will be like rubber when it dry's.