I've been riding glider style boards for over 10 years now and the last few years have got into the design and shaping of these boards. Over this time however, the quiver has evolved into a couple of Josh Hall designs (an Eagle at 11'8" and a Super Swallow at 11'), and a custom 11' Christenson Chris Craft. Now I prefer to create my own and use AkuShaper as my design tool before getting them cut out locally. where I finish them off in the bay before glassing.
I consider a true Glider should start at 11' but they go better with longer lengths, especially being around 100kg.
As for fins, for me I find the 4A template works best as I prefer the wider base to drive off. I've found choosing a fin size will depend on the size of the wave, not the size of the board. Generally though at 1-3ft i'd use an 8", whilst anything head high and above i'd use an 8.5" - the extra half an inch provides a slightly wider base and better drive in bigger waves. Engaging the rail acts as your fin so a 9" or bigger fin would be overkill.
I haven't ridden the DT Prince but my experience from surfing large Munoz designs in the Surftech range was their lack of weight, therefore lack of momentum, not to mention their corky feel. I also hated the 'slap' feel when ridden in even the slightest chop. A PU board just seems to feel and handle so much better.
Having shaped a 12'1" from complete scratch, there's alot that goes into these boards. Best not to over complicate it so I just go with a rolled entry through the first 3rd (provides smooth hull-like feel) , slightly flatter through the middle 3rd (this is your trim spot), blending into some moderate to heavy vee through the back end (great for getting on rail and turnability). My Hall's and Christenson have concaves and assist with a little more speed by straightening out the rocker but these boards are about getting from point A to point B in trim - I choose to compromise a little bit of speed for a better turner and trimmer. Rails blend from soft at the front into a 60/40 through the middle and an edge through the tail for bite - have no problem with catching rails. Wide point is way forward, easily a couple of feet up from centre - assists swing weight and they trim better.
I recently finished a AkuShaper designed 11'6" x 3 3/4" and incorporated all the above elements along with adding 6 channels. The channels provide bite and drive and work extremely well with an 8" 4A. This board is different in that it can be worked on the face of a good sized wave, where as alot of Glider's bulk at the idea and only manage a steady trim. This board comes alive over 3ft.
Enjoying the discussion, just thought i'd add my experience.