Another Quilting Question

First of all, thanks for all the great tips on fraying fabrics. I don't have pinking shears, but might give those a try, because unfortunately, even after hundreds of meters of fabric, I'm still a staunch pre-washer and ironer. I was everything to avoid not only running fabrics, but also shrinkage and to get any chemicals out that the materials were treated with. I've been told that clothing is usually treated with chemicals and should be washed before wearing it the first time to avoid sensitization. It's probably a rare case, but having clean fabric that smells like fresh laundry is nice. And I love the ironing (especially smaller pieces, ironing 5m of backing fabric is no fun at all) - it gives me a chance to look at the fabric again in more detail.

So, to my new question:

I'm working on a baby quilt made of triangles (first time working with triangles, really). Photos to come this week, promise!! I'm having fun with this one and it's coming along quickly.

My only question so far is, when you sew 4 squares made of triangles (HSTs they're called, I think) together so that all the tips meet in the middle, it's a pretty decent lump of seams. I ironed the first seam in the HST toward the dark fabric, and still did the iron-to-one-side on the first set of squares I sewed together. Should I have ironed it open? You'd still have the same number of layers in the end, I guess.

Will this be a problem when I quilt and should I just avoid those lumps? If anyone has a tip, I'd love to incorporate it now before it's too late!