Persoanlly I found loose pants better! Def get a bucket or something to put the bag in overnight, and my experience was that I woke up a few times to empty the bag - turned out I didn't wee much in teh afternoon/evening with a catheter in but loads at night and filled the bag. I got an extra large night bag after a few days. Another tip would be to keep the disctrict nurse numbers you get given handy - they were so useful, because it's all new to you and you don't know what's normal and what isn't, but it's not new to them a tnd they were reassuring. I had 2 or 3 visits from them when I called. Plus - a little urine leakage from around the catheter rather than though it isn't anything to worry about.
I kept everything clean every time I had leakage and didn't get very sore, but can imagine it's uncomfortable if you do so some soothing cream might be useful.