I had trouble with the 1/4" seam in the beginning too, but with practice and now, with a 1/4" foot on my machine, it is much easier. Once you start working with matching corners, particularly the triangles, you may well be cursing all the extra bulk you have. Then again, you may not. If larger seams work for you and you are happy with the outcome, you can really use your own gauge.
Now to the ironing question. In quilting land, we actually PRESS instead of iron. Ironing implies a swirly motion that can easily distort your block. That said, if you press the dark side to the light side, there is a good chance that the dark shadow from the seam allowance will show through. This would be magnified on a large seam allowance. Again, it is your quilt and you can do as you please.
I fought the "ironing" in the beginning too until I realized how much better/easier a properly prepped block goes together. There is a sequence to pressing some blocks that causes them to nest and it helps in the assembly. I won't iron clothes, but I can spend hours pressing my quilting pieces.
Just have fun with it. In the beginning things may not matter as much, but as you progress, so may your personal challenge.