My comment was made for the OP. I believe hes talking about the 40 size. He said he'd added weight to the nose to move the CG to the forward recommended point and he's over a pound heavy. That's a lot of weight (over 8 llbs total weight) and is to heavy for a 40 size plane. That weight is more the 60-90 range, and really needs to be brought down. He didn't say how much weight he'd added to the nose or which engine/battery combination he's using, and I'm sure its not the whole problem, but if he wants to add weight, I'd do it with battery, motor, or both, not lead.

A little more research shows that for the 40 size tiger cub, thats going to be 23 oz/sq ft wing loading, which is in the aerobatic approaching warbird range. Its going to land fast, and require more horsepower to get it off the runway. Not impossible to fly, but more difficult for a beginner.

As for the Goldberg Tiger and the OS-120 AX, if I knew I was going to have to add 18 oz to the nose, I'd seriously think about a 4 stroke 120, or maybe even go with a 1.40 (inverted if necessary for clearance. The specs call for upto a 120 four stroke, and do discuss putting a larger engine and using the tail bracing wires. No its not the full 18 oz difference, but its a lot of it.

And there are always exceptions to every thumbrule. That's why they're only thumbrules.

Brad