I have more luck with puddling as well and now I've got a straight stitch Juki with a large throat which helps immensely but I made tons of quilts and blankets on my domestic and remember the struggle well! I recommend do what you can for the weight like a large table, ironing board, once for a really tricky spot on the side of a large quilt I even bribed a friend with dinner to sit nearby and hold a large part of the quilt sandwich for me
. I also recommend Machiners gloves (although the smell if I store them for more than a day or two in one of my plastic bins is awful, looking for alternatives) and lots of frequent breaks.