sugar type imbalance?

Last Sunday (one week ago today) I started a porter from a kit. The directions that came with it said to add the "malto-dextrin" but did not specify an amount. However, the bag of the malto-dextrin said use four ounces for 5 gallons and it was an 8ounce bag. All other ingredients included in the kit had no measurement instructions so they were added in their entirety. After a little research on the purpose of the malto-dextrin I decided to split the difference and put about 6 oz of it in. Thinking back, the malt extract (even though soaked in hot water) still had about half an inch left on the bottom of the can that didn't make it into the wort. So now that I have a sluggish fermentation, I'm wondering if it could be an imbalance in sugar types. After not seeing any airlock activity after 48 hours, I went to the local brew supply store and got some energizer and yeast. After adding according to the instructions, nothing much happened. I did not measure the OG, but the instructions say it should be around 1043, now it's at 1020. So, there has been a little action. I have agitated it twice with some firm shakes, and each time I do there is decent airlock activity for a while, but I'm not sure if that is helping fermentation or if it's just releasing the Co2 that's in the beer itself. My house is at a pretty constant 68. Any tips or help would be appreciated. Should I continue to shake it occasionally? Should I try the Beano trick to break down some of the unfermentable sugars? I've read that it could produce an undesirable beer that continues to thin over time. Thanks, Mike

Well, since you didn't measure your Starting SG, it's hard to tell how much the wort has fermented. 1.020 seems like it may have fermented some but I can't really tell.

I would not put beano in it, that maltodextrin is supposed to be unfermentable and will give your porter adequate mouthfeel. You were probably supposed to add all of the maltodextrin but I wouldn't worry about that or a half inch of malt extract.

I wouldn't add any extra yeast and energizer until at least four days of no activity. If you were to add extra yeast, add the same strain that was used originally.

Also, make sure you pitch the proper amount of yeast from the start. Here is the pitching rate calculator that I use.
Mr Malty Pitching Rate Calculator

Does the kit say anything about the target gravity? Porters tend to have high final gravities because of the caramels and other long-chain sugars that give porters their flavor. 6 ounces of MD would raise your FG by 3-4 points, so you are at 60% attenuation, not great, but not too bad. Working with Beano is tricky and I would never use it in a porter.

I say let it settle for 2-3 weeks then bottle it.

Thanks for the responses! The target FG is 1012-1014, so once the 3-4 points are subtracted from where it is now, I guess I'm not sitting as bad as I thought. I'm going to follow your advice David, and just let it settle for a couple of weeks before bottling.