20grams is roughly 3/4 of an ounce. If that's the total that's added with all of them then no it's not that much for this size bird but if that's what each double adds then yes that will add up quick.
There is kind of a fine line for the wieght on a plane in my opinion. To light and they can be excessively floaty and to heavy really increases the wing loading and can cause wierd stall habits. There is kind of a sweet spot where it is light enough to float but at the same time heavy enough that it will carry the energy through a manuver. All it what you want I guess but trust me when I say any of the profiles that are "BRO APPROVED" meening they came from a designer on the profile brotherhood website then they where designed to take a beating and keep on ticking.
Take my sbach45 for example. First flight I ripped the wings off (my fault used the wrong type of wood on the joiner block for the wings). It went in nose first at wide open throttle from at least 50' up and the fuse was not damaged at all minus some ripped covering.
If you want some good advice on this plane I would advise looking over on the ProBro site and contacting HazzBro as he is the designer and can give you all the info you need.
Sorry if this has been long winded Im just trying to help you have a wonderful profile experience.
Where might you be located anyways as Kenny of I might be able to point you in the direction of a member of the PROBRO site who is close to you.