The advice you'll get here is don't let travel or cost influence your decision. And your case, travelling from Ireland you'll save money and get a bit of a holiday thrown in, even taking into account, cost of procedure + travel + hotels. As for the inconvienance of travel, the only possible issue that I can think of this, is the akward 3 seconds when you remove you cap to get through the metal detector, but you're in another country , so who cares?
Regarding the scarring from strip, it was never a problem for me playing sport in the rain as I keep a reasonable length at the back and my scarring was pretty bad from inadequate old procedures, but regarding how low can you go on a buzz cut after strip, I'll leave that to the other posters who have experience of this, but obviously will depend on skill of surgeon.
Obviously at your age you should look at the medication (the big 3)options first as 22 is quite young to be considering HT.