Bernie, you can make a forend fit tighter and therefore stiffen the action by adding a shim between the spacer and forend. I use aluminum furnace tape, when trimmed to fit, it can't be seen and is .004" thick with the backing removing, it makes a loose fitting forend snug and you can use multiple pieces if one doesn't help. You can also flat sand a spacer thinner if needed, but I've only had to do that once, so it's probably not likely to happen much.
Tim