We’ve just had an extension with aluminium (Crittal style) doors. The doors are black. I’m now painting all the new plasterboard and there are small gaps to fill around the edges where the skim coat meets the aluminium. Walls are being painted white. I’m guessing I need to use something like CT1 in the gaps rather than caulk but can’t work out whether to go black and then paint over with white or clear? What’s usual? White is probably impossible as there’s too many in and out bits on the doors and I envisage it being impossible to get a clean edge with masking tape and it’ll end up a total mess.