I'd say the lighter rod may feel like your on the limit of it's casting ability so you personally may hold back so as to not snap the tip. The confidence gained with the heavier rod may improve your casting distance to a greater degree rather than the physical properties of the rod itself.

Although without having felt or casted with either rod, it's just an idea.

My 2c worth

All things being equal the DB would give you a futher cast, simply because you can load it more (with the thicker tip you can store more energy). 85gs is at the top end of the sensor, this would make it easier to cast but you wouldn't be able to "wind it" as hard as the DB.

As an example, If you look at the longer surf rods they may be rated as 4-6 oz or some are even rated 4 - 8 oz, this means that you can put a 4 oz sinker on and pendulum cast it a mile, or an 8 (even 10oz) sinker with a OTG type cast.  trying an 8-10oz pendulum cast will leave you with a broken rod.

The thick tip will reduce the sensitity when fishing though.

every rod (or setup rather) will have a Plateau, the distance you cast will be related to the stored energy in the rod, the speed of your lure in the cast, your line thickness, reel design and of course your timing.

Thanks very much for your input and advice guys

Really appreciate it. Still deciding on whether to commit to getting the demon blood rod but will scout around and will most likely make an impulse buy in the next few months

Cheers