I used a fresh can of June Tailor spray baste on this project and was not very happy, I will be trying glue next. I have some old cans of the same brand that have been sitting for years that I felt gave me a better performance. The scent seemed very strong to me and I waited a couple of days for it to dissipate before actually quilting.
I know the temptation is to baste the whole thing at one time, especially with a small project. That has never ever worked for me! I do it in roughly 1 foot sections but I have short arms, some of you may be able to work a bit larger but I've found quarters are too big for me to get good results.
First get your quilt back ready, press if needed. Do a few stretches for your own back! I typically work on my queen sized bed since I have a small house with no large tables, the bending over really gets to my back. When I was working, I had conference room tables available and that was much better! We had a thread recently about places to find such a thing, in our area Fire Stations have meetings rooms, as do libraries, senior centers, schools, etc.
I've been doing it as described below because it gave me the best results when I started, I'm thinking about putting the backing on the same way I do the top, that is on top of the batting first instead of as described below where I put the batting on top of the backing. Think it might save me some bending over.
Once you have the back right side down and secured in some fashion (tape, pins, cans) layout the batting. I air fluff mine in the drier for a couple of minutes to get out creases or fold lines. Loosely position over the batting and fold in half in the middle. I usually work across the short sides of the quilt but I guess that doesn't really matter. Holding the spray baste approximately at my elbow length above the quilt, I spray onto the quilt back roughly 1 foot of surface at the fold, pull down the batting over it, smooth it out, and repeat. I like using a 6x24" ruler to help smooth.
This layer takes the most time and is worth the effort. Once you have sprayed the batting down and smoothed it from the batting side, flip the whole thing over and smooth it from the fabric side. This is your last chance to make it smooth and nice so be fussy. Once you are satisfied it's time to flip it back to the batting on top.
You repeat the 1 foot intervals with the top, spraying the batting layer, smoothing on the top. Do a quick check on the bottom layer to make sure it's still good.
You may still want to slip in a few safety pins until you get some stabilizing quilting in if you have a standard throat space. But it's very few, not the "put your hand down" with pin basting but a few around the outside edges and a couple in the middle.
It took me a long time to get used to the right amount of spray, and a high loft batt does react differently than something like Warm and Natural. I think most people over-spray in the beginning. It should never discolor the fabric or be so much you can feel a stiffness, just an invisible stickiness with all brands, some have more of a sheen to the product which can make it easier to see than some that are more matte. If you are having problems with gummy needles, it is too much spray. You might try waiting a couple of days with the quilt fluffed out and airing. Again, I know I oversprayed in the beginning, and would sometimes have issues when I washed the quilt before giving it that the spray would still be sticky and attract lint. While the spray does dissipate over time, once you've put your top together you have about two weeks of prime time, even after that the layers will still stick together.
And speaking of overspray, yes! be aware that you don't want to sticky your house. Protect your surfaces and be careful where you aim. I have end rolls of brown kraft paper I use to cover my bed. I would get cheap painter plastic drop cloths for when I was working in the office. Vinyl holiday table cloths (especially the type with flannel on the back) are great.