How to prepare the roof for a PV system upgrade in advance?

In the next few days we will be covering the roof with shingles. For budgetary reasons, we don't want to upgrade the PV system for about 5 years. However, we are already making preparations now to minimize future interventions (e.g., in the roof insulation level).

The roof tiles for the photovoltaic system as well as the empty conduit will be installed in the utility room of the building.

On the upper floor, the cables from the roof can be routed in the empty conduit to the building service room.

Roof orientation: south/north

Horizontal area per side of the roof: 9 m x 4.5 m

Roof overhang: 40 cm

DN: 42°.

Windows in the roof: 4 pcs

Placement of through tiles on the south roof directly under the ridge. Cables can be laid under the shingles on the north roof in case it will also be used for the photovoltaic system, which I currently exclude. A DN40 was planned as a blank duct. 

Any advice on the planned procedure would be appreciated.