Hi Fintan,
Sound advice there from Dennis. Try a few Rods before you commit to anything. You don't want to end up with a carbon footprint like Paddy.
Best way is to get up to a meet and have a try of a rod or 2. Do you prefere the 150g & 175g or do you want to try the lighter leads. I think the HSM would be nice for the 100g and maybe the 125g, so maybe you only need something for 150g and if it handles the 175 all the better.
Be careful, this casting lark normally ends up in a reel collecting binge.
Kev