I'm down to Nautibuoy tomorrow and will take some measurements which may help.My keel bulb is about 60mm from hull in rest position on trailer ie lower cg.
She sits on an old but sound 4 wheel trailer with twin parallel longitudinal box sections to which coupling attached one end. Wheels carried on a rectangular frame attached to longitudinal sections. Its obviously been adapted from one for a long keel rolled directly onto rollers on longitudinals with now two bridge pieces taking hull weight: one around the log position (care needed!!) and one probably about level with bridge deck B/H
Keel bulb sits onthe two longitudinal sections where two roller brackets are splayed to help locate it.
4 adjustable swivel pads on upstands stop tipping sideways
Since I only use trailer for storage (weight off tyres) the rear bridge doesnt bother me as crane lift on/off. If trailing you will want to have gap to let keel bulb pass as you float her on.
Even with 2 in cockpit and say 50 KG of engine etc she is quite stable on trailer.
I dont know where you are based but if you want to look yourself she is outside the main door to Dell Quay Sailing Club.