I have a medium heavy fenwick hmg and I'm looking to get another casting rod for lighter baits. I found the okuma Scott Martin rods and the 7' medium heavy/ moderate fast has a lure weight rating of 3/16-3/4 ounce. My thoughts are that it would be good for treble hook baits, leaving my fenwick for heavier, single hook baits. So what do you guys think? Sound like a solid plan?

You logic is sound but I don't have hands on with either of those rods. If the mod fast is real stiff it may defeat the purpose but if you can believe the 3/16-3/4 rating it appears to have some tip. 

Go here and watch Scott himself explain the uses for his signature rods

https://www.tacklewarehouse.com/Okuma_Tournament_Concept_TCS_a_Casting_Rods/descpage-TCSA.html?from=basres

From what he is saying you are best off with one of these two the 6'9 mh mod fast or his 7' mh mod fast. They both look good.  One thing I will say about Scott Martin, and for that much Mike Iaconelli, they both fish their sponsors equipment and in both of their cases they do fish their own signature rods.  I have watched too many SM Challenges and Scott in tournaments. Frequently he shows you or tells you what rod and reel he is using.  In Ike's case he fishes some of his signature rods ( it is hard to hide the purple hue to his signature rods) as well as other Abu rods.  I respect them both for that.  It is the opposite of anglers like his dad, Bill Dance, or Jimmy Houston. They seemed to put their name on anything at any time. 

Yeah I was thinking the 7' mh would be the ticket. I've read a lot about his rods, pretty interesting that they all have slower action.