I really don't think the TX50 is worth £20 more than TX40. The TX 40 reg breathes good, you can use it for any mix and is good enough to go to record depths. I have never tried splits, I quite like jets, I find them more managable than quattro's, which I think are to long for me. I wouldn't bother with a computer, I think you are better off with a dive timer and stick to tables. Though I have a computer, it come with a warning " not to be used for professional diving." I like to plan a dive using the no stop limits of Royal Naval tables, its one sheet easy to learn and use mentally, I add a 3min 5 metre safety stop, but I know I am safe if I need to ignore it. It suits my diving pattern of average 30min dive, max 2 dives, on a weekend. I have got a tusa liberator Stab but I think I would get myself a steel back pack and a wing, I wouldn't get an aluminum tank, I have got steel Fabers as you need less ballast. Get yourself a good shot weight belt, they are much more comfortable and save a lot of kidney ache, I wear a harness type, but I am a corporation man. I dive all the year round and use a front entry dry suit, but the water here never gets warmer than 14C in Summer and can be 4-7C in Winter. I have never tried a wet suit. I don't know the conditions in Texas, over here a good torch is essential. I like my guages to have big numerals because I need reading glasses. I use a wrist compass. Regards a mask, the most important thing is how it fits your face, take care to get one that seals well, I have great difficulty there. Maybe its a bit retro but then I am over fifty. What ever you buy, have fun and safe diving.
Regards,
Budgy