Being from the same part of the world, I have had steers that I've had to slick in the summer to keep them eating. Ive never done it on one in the spring.
Honestly, the shedding combs available now have revolutionized getting rid of dead hair. Infinitely better than griddle bricks, etc. I'd suggest using that at the first sign of shedding in late Feb/early March.
As far as Im concerned the stuff about clipping heads is an old (new) wives tale. By summer, they are going to have shed their winter hair no matter what. Genetics will determine how much they grow back.