I did my PPL in a 172 back in 2003/4. Total cost at the time was around 7.5k IIRC, got in around 50h. The problem for me came afterwards - buying a share in a lovely little 2-seat taildragger that needed a lot of TLC and often had niggling problems. At first this was all part of the 'joy' of flying, but for me I realised too late it also eroded my confidence. I was always keeping half an eye out for issues, and became reticent to take friends and loved ones up. My hour long drive each way to the field meant a quick bimble was a half-day affair, and my hours dwindled along with my competence. In the end a move away from the area sealed it, and I haven't flown in 10 years. I'd dearly love to get my license back, but I simply don't think that will happen now, finance-wise.
I'm relating this to you as IMHO 12 hours a year in an aircraft you have confidence in will, I think, be OK. 24 more than adequate. Its the quality of the hours that count too I think.
As to the height thing, I'm 6' and have sat in an Icarus C42 marvelling at the room inside. I think you'd have no issues in something like that, unless you're 'all leg'. I chose the 172 to learn in as I'm a broad chap, so two abreast in a 152 with my first instructor (nickname Chunky) was... interesting.