in my garage conversion, i'm laying insulation on the unused attic
floor; ie, right on the flat plywood flooring, not in b/ joists. i
can't get insulation blanket around here in r30, so i'm limited to 15"
and 24" width batts x 48" long. the cost of 15" suits my total-sq-foot
needs better, so i'd like to get it; but will more seam connections
with 15" result in less insulating power?

also: around here, neither lowes nor HD stock r13 in the 24" width.
they don't stock it and say they can't get it. i thought 24" was as
standard a width as 15". Is that not so?

thanks

ps: cross posted this to one other logical ng.