Increasing weight capacity on downrigger. Any engineers onboard that can help?

I have the Scotty laketroller and I'm running a 4lb downrigger weight on it. Though the manual states "Maximum recommended weight
is 2-3 lbs", it seems 4lb works just fine. I would like to run a heavier weight but am not keen to upgrade to a 1050 if I don't need to. Then it came to me that shortening the arm will lower the torque placed on the base of downrigger. With a boom length of 12", I typically angle the boom backwards to get the DR ball closer to centerline, since I don't need the entire length of it to clear the gunwales of my Revo. If I were to shorten the boom by about half, how much of a weight increase can I potentially go up? And what formula am I looking for? I'm not looking to run a 15lb pancake or anything, although 6-8lb would be great.

I have ran 6lb and occasionally 8lb on the lake troller.
You will be ok with 6lb. 

One other thing to consider is replacing the wire line with braid if you haven't done so already.  The braid cuts through the water better with less humming.  You may accomplish the same results without having to use a heavier weight or shortening the boom. 

I have ran 6lb and occasionally 8lb on the lake troller.
You will be ok with 6lb. 

Thanks, it's good to know it'll at least take it and not completely fold, however I think i'd probably want to strengthen the backing for my scotty mount..

One other thing to consider is replacing the wire line with braid if you haven't done so already.  The braid cuts through the water better with less humming.  You may accomplish the same results without having to use a heavier weight or shortening the boom.

I'm running 65lb braid on it right now, but the extra blowback is coming from my 8" Hotspot flasher. I may consider reducing resistance and running an inline flasher instead and just save the work, trusting that a 6lb will be fine.

I shortened the boom on mine. You will need to bend it upwards if you shorten it so that the pulley still is inline with the spool. I also run 65lb metered braid to a rubber snubber and then my weight.

Most days I run 4lb. 6lb sometimes and it handles it no problem.

In the ocean with a 4lb weight and 8inch dodger I will get some blowback but it is very manageable and I just keep track of where I’m at on my metered braid.

I shortened the boom on mine. You will need to bend it upwards if you shorten it so that the pulley still is inline with the spool. I also run 65lb metered braid to a rubber snubber and then my weight.

Most days I run 4lb. 6lb sometimes and it handles it no problem.

In the ocean with a 4lb weight and 8inch dodger I will get some blowback but it is very manageable and I just keep track of where I’m at on my metered braid.

that's great to hear. Seeing that others have run heavier without modding, plus shortening the boom I feel I have more confidence running heavier now. Yeah, I noticed you gotta bend it upwards a bit to level the pulley. The metered braid is a great idea too.