It is an interesting question regarding environmental reasons for not allowing atmospheric discharge of the oil vapour (this amounts to absolutely fark-all oil vapour carbon content compared to the amount of diesel you are burning) . Technically when you burn the oil vapour it is oxidised and contributes about double the weight of the oil to carbon dioxide. It seems far more environmentally responsible to use a decent oil vapour separator (catch can) and plumb the collected oil back to the sump and vent the air pressure.
The only concern is whether the motor would be better off having crank case gases sucked out by action of the intake creating a slight vacuum before the turbo OR if it is enough to just vent the crank case pressure through a catch can to atmosphere creating as little restriction as possible.
regarding burning the oil vapour, the problem is more that it sticks to the intake manifold and valves creating a thick black carbon deposit and gradually blocking up your intake, making your vehicle drop in performance and efficiency. Just have to take off an intake manifold to see how blocked they get regardless of if you have an intercooler or not.
The fuel filter and glass bowl idea sounds like a good way to see how much is collecting. Any catch can is better than nothing and although the best catch cans like the Provent do work well, they tend to also block up faster. So whatever works best for your application is the best solution.