Problem: Beneteau 461 quickly gets over powered going to wind with 140% roller furling Genoa. Rolling (reefing) the Genoa not a good option.
Solution: (a) Install Solent stay and use hank on Jib for Breezy conditions.
(b) Buy a wire or spectra luff Jib.
Pros and cons? Better options?
You CANNOT 'just add' a solent steay without appropriate 'reaction' stay, such as an additional backstay or running backstay (or horrors, intermediate stays)
If you dont have a 'reactor' for the solent, the backstay will react with both forestays; hence, each will be at ~1/2 the tension of the backstay. The result will be a god-awful shape of EITHER the genoa or whats on the solent.
If you dont elect to add an additional 'reactor' when adding a solent you will have the problem of 'differential' (changeable) loads in the head wire dpending on 'how much Sail Area is exposed .... and then the stay that is not supporting a 'flying' sail will receive 'most' of the tension and the stay flying the unfurled sail will UNLOAD .... the unloaded stay (with sail flying) will cause a extremely 'powered up' sail, sagged off to leeward (BAD pointing configuration, the draft will become 'aft' .... the boat will NOT point, will hell aggressively when going to weather, and the boat will be SLOW.
Your signs and symptoms kind of suggest that your present rigging is too damn loose (creating a slack forestay). So, suggest you contact a rigger who also races to assure that the rig tension is CORRECT for your sailing venue ..... THEN contact a sailmaker to possible correct the luff shape ... and possibly add a foam luff, etc. so that you can REEF the foresail. Note: most properly designed and cut foresails can be 'reefed' by 30+% and still have a modicum of proper sail shape. 140% X 70% = 98%
Question: What happens when you reef the MAIN down to the first reef, down to the second reef?
If you're reefing he the jib instead of the MAINSAIL, maybe you might consider reefing the mainsail first.
Otherwise if you have a double tracked furling foil .... buy another but smaller jib/genoa and learn how to 'peel' a foresail (changing jib using one foil and while sailing).