Best place to drill through aluminium door to fit maglock

[OldKettle]

Hi,
I need to drill through an inward opening aluminium door to fit a Z+L bracket for an electromagnet lock.

I am only fitting the lock to the left side door shown in the pictures.

I would like to put it in the top right corner (A), but I am not sure what structures might be inside the frame at the corner, and wonder if a more central position (B) might be better for drilling, with less chance of hitting anything inside the frame

The door has a cylinder lock on it, and so the magnet won't be the main lock. I just want to have it so that deliveries can be left in the porch.

I just wondered if anybody could please advise.

 

[crank39]

Height wise both positions are good as you are clear of the glass with the screws, if you choose A make sure that if theres no shootbolt in the top of the door that the 2 right hand screws would interfere with its operation, B is fine

 

[OldKettle]

Many thanks.

Could you please also advise on the type of fixings you would suggest.

The bracket comes with 10ga wood screws, which I will use for the bracket on the wooden frame, but what would be best for connecting the bracket to the aluminium door?

These are the shortest 10ga self-tapping screws I can find, would they be appropriate?

https://www.toolstation.com/stainless-self-tapping-countersunk-pozi-screw/p18348

Should I be concerned about using stainless steel screws, given that it is an external door that tends to get quite a but of condensation on it, that might cause corrosion with the aluminium?

 

[crank39]

Search out Tek screws, pan or hex head

 

[OldKettle]

Search out Tek screws, pan or hex head

Thanks. I ended up going for these BZP carbon steel ones, which seemed to work well (drilled a 3mm pilot first).

https://www.screwfix.com/p/easydrive-carbon-steel-self-drilling-screws-4-8-x-16mm-100-pack/68505

The screws have 8mm of actual thread, and the bracket is 4mm. The screws cut well and seem to have made a good connection.