Boat trailer draw bar modification

Hi all, Hoping for a bit of guidance on a boat trailer. I have an late 1960's ski boat on the original trailer and i would like to put brakes on the trailer to bring it up to current compliance. Also looking at extending the draw bar a little to hopefully improve backing the trailer as the nose of the boat comes close to hitting the back of the ute when reversing and it's just generally a bit of a pig to reverse. As you can see the previous owner has cut and moved the nose bar to keep the boat back on the trailer to make it easier to reverse. However this results in shifting a lot of the weight too far over the axle. The chassis channel is around 3.2mm thick and there is a approx 60mm angle 6.5mm thick set back with the first roller fixed to it. My thoughts are to cut out the existing tow hitch plate and insert (and weld in) a new draw bar that will continue through to a new cross piece that will also be used to add a post for a winch mount and so get rid of the old bar that goes over the nose of the boat. So I was wondering what size draw bar should I use and how much longer can I safely extend it past its current set up? I was thinking of working out where the nose of the boat will sit and then locate the cross bar around this area and run the winch post from the cross bar. The end result would be similar to the pick below. Any help is appreciated. Cheers p.s. sorry for the formatting, for some reason the formatting isn't recognizing spaces etc.