Photovoltaic system, house, or garage roof?

Morning,

Last year we built a massive KFW55 house new.
We just managed to do it before the photovoltaic requirement.
Nevertheless, of course, a photovoltaic system has to go on the roof.
We have a heat pump and roughly estimated 6000 kWh/year total consumption.
The photovoltaic system should be as small as possible but as large as necessary, roughly thinking maybe about 8 kW.
Thinking initially without a storage system. That is all still unclear.

I am currently building a massive large garage/workshop with about 90 sqm usable area on 2 levels.
The garage will have a normal 38-degree tile gable roof.
The house has a 45-degree roof pitch.
In picture 1 you can see the house roof, oriented south, so actually gets sun from morning to evening.
The garage is then at the back in the other corner of the property, also facing south. Picture 2.

Garage roof area on the south side is 60 sqm.

In the garage I have all large three-phase devices, like welding machine, compressor, lathe, car lift, etc.

I now have a 75 mm Kabuflex empty conduit in the floor from the technical room to the garage at the back.

There is a NYY 5x16 mm² cable 30 m long as the main supply line back there.
There is also a CAT7 network cable for the network in the garage.

We have already done the photovoltaic preparation in the house, meaning space in the distribution board and empty conduit from the technical room up to the roof.

But now I have realized that maybe it would be better on the garage roof—you can get to it easier since it's not quite so high.
Our technical room in the house isn't that big either.
In the garage I would have enough space on the 2nd level.

My main question now is, if I put the photovoltaic system and storage in the garage, I would connect it back there, 5x16 is enough.
The question is whether the storage is harmed by the peaks that happen during welding etc.!
There is constantly switching back and forth.

If I mount it on the house, I would then have to lay a cable from the garage to the house for the photovoltaic system, maybe 5x6 mm², right?

For the basic planning, I want to know now which cables I need to pull in the empty conduit, because it is still possible as it is interrupted halfway behind the house.

If I mount it on the house I need the following cables:
- 5x16 mm² NYY
- 5x6 mm² NYY
- CAT7 outdoor cable

If I mount the photovoltaic system on the garage I need:
- 5x16 mm² NYY
- CAT7 outdoor
- CAT7 outdoor for the photovoltaic control in the distribution board in the house

Long text, what do you say?

Is the roof of the garage and the house oriented the same way and do they get the same hours of sunlight? In my opinion, the garage gets fewer hours of sunlight because it is still in the shadow of the house in the morning.

Photovoltaics on the house are better oriented in winter when the sun is low.

I would install the photovoltaics on the house.

But ideally more and on both.

We have the same consumption, but a 13kwp system and 10kwh storage. Now in March/April, the storage early in the day has between 5 and 30% residual charge, the heat pump then already has hot water ready and runs its first heating cycle from 7am. I would also take the house roof because, the technical room is heated, distributor box and meter on site, reliable LAN supply, everything is also in one room in the future.

In terms of consumption, a full occupancy with full feed-in without storage is probably the most economically sensible. I know all the dissonance lamps go off, but mathematically it would be like that, unless one assumes permanently exploding electricity prices.

I actually need to check if the house casts shadows on the garage roof, I almost don't think so, between the house and garage are 9m. I'll keep an eye on that. I have lasured the rafters and purlins in the past few days, we'll set it up in 2 weeks. Then you can really see it. I would send another picture then.

Overall for everything 6000kW, but I don't know for sure yet. It's just my estimate, and what I pay in electricity rates.

From October until now (almost 6 months) we have 3050kW, that was during winter.

I think it might only be 5000kW.

With new builds, you only get the real values after about 2 years, the construction moisture still in the walls apparently makes a big difference.

What difference does it make if the technical room is heated? I would have the secure data connection in the workshop too if I lay down the network via LAN.

I think it might only be 5000kw.

The lower the consumption, the more worthwhile full feed-in is.

What difference does it make if the technical room is heated?

Photovoltaic technology (especially storage) also does not like frost.

As said, cover everything, as full as possible.