Using maltodextrin post fermentation

Long story short, due to a inaccurate thermometer, I massed at 149 instead of 154, missed my final gravity (under) by 5 points and am considering adding maltodextrin to bring some body back. This is a brown ale recipe that finished at 1.014 but was suppose to finish at 1.019. I've tasted it, and it could use some body to go with the malts. It was an all grain batch.
Interested in hearing about experiences, amounts, techniques, etc.
I'm assuming I'll need to dissolve it first. Four ounces for 5 gallons? I've never used maltdextrin so I'm wondering if it works, does the job, or ends up tasting funky?
Thanks!

Normal dosage is around 8 oz for 5 gallons, 4 ounces might not be noticeable. I have seen recipies with 16 oz. If you have a caroboator cap, I would put some beer into a soda bottle and carbonate with different dosage rates until you like the ratio, then scale it up for the whole batch.

You can add it at bottling or kegging. Boil up 4 to 8 oz in a pint of water. It will totally make a difference. I have added it even after my beer was kegged and carbed.