Of course thicker rods are better, but that won't help if his Liquidator has 1/8" lugs.
That is certainly correct, and for right now, he's kinda stuck.
He
could shave off the outer 3/4 of the existing LLs and glue some 3/16 lugs into the "saddles", but then you have re-painting or else it looks like doooky, and if you paint then you have a chance of ruining the decals, and it's more trouble, and it's probably not worth it
Also, it is likely that 8 or 9 times out of 10, he will be able to launch just fine using a 3 foot, 1/8 inch diam rod, even for a relatively large modroc like a Liquidator. But (PharmrJohn, this part is directed to you) if you want to have the flexibility to be able to launch slightly heavier modrocs safely, or if you want the capability to continue launching on slightly windier days, you need to step up to a bigger launch rod diameter. This will have significantly less motion or whipping and will get your rockets off to a straighter flight. Larger rod diameters also work better if you want to use
lengths greater than 3 feet, which also helps your rockets off to straighter flights. Even if you only increase to a 4 foot length, it will make a difference. Order a supply of 3/16 LLs and keep them around for replacements, because most of the manufacturers seem to automatically go to the 1/8 size.
I hope you guys will excuse my conservatism, it's just that I recently finished helping in a legal matter where a kid was nearly killed---and my evaluation of the cause of the mishap was rod-whip (with aggravating circumstances). This is just so blankety-blank easy to eliminate that I am now a BIG pusher of solid launcher setups. Launch rod size is a poor place to skimp on launcher safety features. This is one place where I feel that bigger is indeed better, especially for beginners, who don't understand the physics (or don't even have the training to begin understanding), or cannot recognize marginal wind conditions, or who don't build their modrocs with "perfect" fin alignment and balance, or don't have an experienced advisor present. Keep in mind that the 1/8 inch size was selected way back in the day when modrocs as a whole were MUCH smaller and lighter (C motors were the biggest thing available), the problems of rod-whip were not well understood (or even experienced yet), and a certain company that sold modroc supplies primarily by mailorder had to consider shipping weight and cost. Now we have bigger modrocs, and while they
can still work on 1/8 rods, it would be good to change to something bigger at the earliest convenient point---in my opinion.
And I still agree with everything else you posted.