Mirror Tinting worked out very well from a privacy perspective because our living room comprises three sets of sliding glass doors with glass panels on each side - the downside is that it makes the room darker during the daytime. But from a heat protection perspective I doubt \it is of any real benefit. Some of the distributors of mirror tint film have glass display boxes set up with a 150 bulb bulb in the middle, that is meant to show the degree of benefit of installing one type of film over another, or none at all. All of that is well and good if you leave the light on only for a minute or two, leaving it on for several hours is a totally different story. You mention late afternoon, that's almost certainly the product of accumulated heat being released from the walls and steel rather than from windows themselves.

If there is any real benefit of using tinted film it is overridden by the fact that heat transfer takes place from the walls and metal window frames, into the glass and onwards into the room thus bypassing the film, the best approach is to prevent it from reaching the walls/windows in the first place. Window tint film might be useful in conjunction with wooden window frames where there is a thermal break between the concrete/brick wall and the window glass....using double pane glass doesn't really help either unless that thermal break exists.

A far better approach subsequently was to use wood slat blinds on the outside of the house, under the eaves, we have four sets that we raise and lower based on the time of year and time of day and they work really really well. The blinds cost about 1.5k per set (2 metres long) and ours have lasted six years thus far. The blinds roll up easily and can withstand even the strongest wind when rolled....it's a simple installation although I do offer a remote installation advisory service which will benefit you enormously, should you decide to buy!

Chiangmai.

A far better approach subsequently was to use wood slat blinds on the outside of the house, under the eaves, we have four sets that we raise and lower based on the time of year and time of day and they work really really well. The blinds cost about 1. 5k per set (2 metres long) and ours have lasted six years thus far. The blinds roll up easily and can withstand even the strongest wind when rolled....it's a simple installation although I do offer a remote installation advisory service which will benefit you enormously, should you decide to buy!

Going from personal experience(s) I'd go down the wooden window blind road. We fitted them to all of the windows at our house in Surin, Bit oversize so as to cover the metallic frames thus lessening the conductivity of heat.

No complaints to date after some six years of service, the only maintenance has been a coat of varnish to the wooden blinds every year or so to protect them from weathering. No ant or other insect problems either

A tip though,we fitted the blinds with small hooks and the house wall with corresponding eyes and some short strong cords attached to the eyes at the down and up  height so as to be able to anchor the blinds in place whether they are up or down thus minimizing their movement in the event of hot sunny windy days we are subject to at times in Surin.

I just accept the fact, if my leccy bill is less than 3,000 baht per month, its a bonus, didnt move here to sweat my bollocks off and live like a somcahi.

House design and placement play a large part, determined by the land plot and access.

Get some quick growing banana trees in for some shade, get some proper heat reflecting paint for those walls.