Hi Craig,
Yes, I am a huge fan of the HS forward screen.
It has 3 potential uses:
1. Triggering HIP/mines etc
2. Soaking up FP with less valuable units
3. Tying up SFF opportunities.
As for #1. Triggering HIP/mines etc, there is little you can do except the most obvious... don't place these assets in locations that are eaily guessed. Mind you, I also use the HS to Search as well, a HS TI in the middle of a potential Minefield is not much of a price to pay!
As for #2. Soaking up FP with less valuable units, while the loss of a HS is not as important as the loss of a full Squad these WILL add up. Death by small cuts is still death! Still, if it is a matter of my 9-2, HMG 468 copping a 8FP -2 shot or a HS then I know which I would choose to sacrifice!
As for #3. Tying up SFF opportunities, I think this is something that you don't start to see in players until they mature. This is a vital tactic, even if my opponent doesn't waste his 4FP -2 shot at my HS he is still going to have just a single shot at what comes afterwards... my HS is going to be sitting right next to his unit and even though it will take the Final Fire shot I usually have a number of units FG-ed behind it to exact revenge. If the Final Fire is not effective then I can jump into CC and potentially tie up an Enemy essentially making him useless!
How to beat these tactics?
My favourite way is a defence in depth... the rear MGs and units can take out the pesky HS leaving the foremost units the real job on those that follow. Remember the death by little cuts... the more HS that you kill the less of a HS screen he has... and you are still killing the enemy!
Get the HS first as they rush across the open ground and worry about the rest later. Your opponent will either have to make more HS for the screen or he will have to do the dirty work with Squads... either way, you have taken out some of his OoB.
If you cannot defend in depth then I would usually hold fire until his FG/stacks are in place and then try to take out the key figure in the FG or take out the biggest stack... when there is little room for you to move then there is usually little room for your opponent though!