I typically use preshrunk white flannel. It gives it a bit of stability without heaviness and helps keep the little tufts of minky fuzz from being pulled to the surface of the quilt top. I've also used silk batting which gave a lovely drape. Flannel is less expensive though. Try Quilters Dream Angel. Also nice drape and is fire retardent.
It will work either way, but batting will add a lot of weight to an already-heavy project.
It's not necessary to use batting with Minkee, so it's your call.
Load with the selvages pinned to the leaders and make sure the side clamps are loose and not stretching the Minkee at the sides. I actually pin the top and the Minkee together all along the sides and then fasten the side clamps over a pin. It seems to stabilize the stretchy Minkee a bit and reminds me not to tighten the elastic of the clamps too much.
I didn't quilt it the first time. It was finished in 2000 and spent a small bit of time on the bed. It originally was destined for the makers DD who, after it was finished "didn't like it very much." Those ungrateful kids!! After putting it in a quilt show, necessitating a sleeve, the maker hung it. Twelve years later the same daughter notices it in the guest room and decides she wants it now.
The damage was discovered when the customer wanted to launder it.
It was very nicely longarmed using all cotton thread and without a stitch regulator. Some of the stitches were long but nothing unacceptable.
My thought on why this happened--
Cheap cotton thread--only the bobbin thread had snapped. The top thread stayed intact, even though that's where sunlight would weaken the thread.
Stress on the diagonal--if you sit on a diagonally stitched quilt on a bed, the fabric will naturally stretch on the bias and weak thread will eventually snap. If your hubby sits on the bed in the same place every day to put on his socks and shoes, get him a bench or rotate that quilt regularly if you can.
This might be the key--the quilt was stitched very far apart. If I was planning diagonals on an Irish Chain, I would plan to stitch through every corner, making the lines of stitching fairly close together. This one had every-other square stitched through. About 3 1/2" apart. Lots of spaces unquilted. I think the lines of stitching so far apart contributed to the stress and breakage.
If you're interested, the other problems I ran into--no color thread I had matched the two green original threads. My stitches, even set at 10 spi, were obviously smaller than the original. I didn't take time to remove all the problem top thread that I stitched over. Her budget was tiny and I did much of it as a favor to this great regular customer and friend. I showed her the threads which she is happy clipping--both front and back. I had to remove the hanging sleeve to get to the problem areas and she'll need to stitch it back. I recommended that she tell her DD to fold it at the end of the bed or use it folded only for display. I can't imagine it has a lot of hard use left it it.
It was quite an education for both of us!