Growing up in Alaska I didn't have much access to strawberries but I did have rhubarb and made a variety of jams, jellies, etc. with it. Don't have my Alaskan cookbook any more that had a ton of recipes (I don't particularly recommend the one that includes bananas anyway...).
Rhubarb requires a lot of pectin because it doesn't have much of its own. The amount of sugar is also needed to help set the product but if you don't mind a thinner set, you can reduce the sugar.
The best way I think to reduce the sugar is to cook down the rhubarb first with about half the sugar the recipe calls for. Keep it on a low/medium heat so it doesn't burn, it will probably be more brown and less red when you are done. When it is about where you want it, add the pectin then. Since you have the pectin it isn't so much the issue, you can also try chopping some apples finely and adding it to the rhubarb. Will help sweeten and apples have lots of pectin.