Hello,
I use the 505 spray all the time to hold my layers together on a quilt or a table runner etc. I can spray my object and fold it up and haul it to a class and it stays together. When I first used spray adhesive I sprayed every inch, now have a little lighter hand with the nozzle. It's up to you how heavy you spray it. I always spray my batting, not my fabric top or bottom, that's how I was taught.
With the spray you don't really need pins or to baste, but that's up to you, too. I love the spray adhesives and think 505 is the best I have tried, and it doesn't have the odor some others do.
Have I ever ironed after using 505 to set it? No I haven't.....and I haven't ever seen or heard of doing that before, so don't know if that works or not. If she teaches quilt classes and does this it just could be a new great hint! Thanks.
Have a great day.
Bev