Hi all,
this is a real problem especially if your windows are facing west... like our apartment.
It was so bad that the west facing walls were hot in the late evening and start to dissipate the heat till 9pm.... not funny I'd tell u.
We did not choose solar film in the end as the film will deteriorate after 5 years and it was a nightmare to remove. My sister's apartment just went through that process.

Instead we chose full height curtains to insulate the entire west facing wall.
In addition, we hung "blackout curtains" on our normal curtains, which helped to reflect a lot of the radiation coming.

It is now a lot cooler and we save on air conditioning bills too!

See our renovation blog here.