Hi everyone

I have a few extra baseboard rad cores left over (opted for in-floor instead) and was wondering if i doubled up on some of my existing baseboard radiation zones, could i expect to get lower return temps on those zones? The cores are “slant fins” 3/4 cooper with aluminum fins. My new boiler is a condensing type and from what i’m told, the lower the temps you run in the system, the better. I guess in a sense, i would be attempting a make shift high output rad to lower my return water temps. One other thing, can you “Over BTU” a zone when using a condensing boiler? Thanks to all!