Weight for kayak McKay Crab pots

I just purchased two of the McKay kayak crab pots and I am wondering how much weight I should have to keep them in place while they are soaking. I plan on using 5/8" rebar. If I zip tie three 24" pieces to the bottom that will be about 6lbs. I like having the rebar on the bottom as it digs into the bottom and helps keep the traps in place (I think). Does anyone have experience with these smaller traps? Comments or suggestions?

Only had 2 pieces of rebar in mine, and never once had an issue.

I agree with SD2OR, I have modified some of the SMI 24x21x12 inch pots they sell at BiMart and Cabela's (I love the way they open up top, plus the BiMart sale price    )...anyway, I cut them down to be 24x15x12 inch and lock the back door closed so they have 3 doors (2 side doors and a front), position my bait towards the back. 

You can see here that I have 2 rebar pieces on the bottom for extra weight, probably 4# total, plus I wrap some pencil lead on each of the doors to go give them a bit more closure weight.   This has worked well for me in lower CoosBay moving tide and also ocean trips. 

On the full size 24x21x12 inch version I will put longer crossing rebar pieces on the bottom, more like 6#.

cheers, roger