If Q directed at me, that may be the case now. I can't remember if I entered IM as a Pro during that period, or it was non-IM events as an 'elite'. Hopefully someone on here has done this, and pref a current Pro.
I can't comment on the current system, but I got my pro license for the period 2009-2011 and here's how it worked -
At that time it was generally considered that a sub 9 hour time would justify 'going pro'. The process simply involved sending a letter of request to the BTF with a little background including recent race results. I had just left working a 9-5 job to both coach and train and dipped under 9 hrs at Roth, so I felt that officially becoming 'pro' would benefit me in a number of ways, and in particular:
1. racing privileges like diff start waves/times, transitions
3. more (self employed) taxable expenses
I received a certificate (signed by the Head) confirming I could race as a Pro for long-distance triathlon for the following year. And that was it!
I have heard of some of my peers also going Pro with personal bests of circa 9:10-9:15 (fast course), so I'd suggest you aim for this figure first.
Some people may consider themselves Pro anyway if they have the cash to train full-time. But for official status there is no point becoming a Pro and racing in the corresponding cat at a race (if indeed you are given the card/certificate in the first place!) if you can't keep up with the rest of the field. And I'll be honest, you are probably a good 2 years of hard work off that level. I've seen and coached a few people who have made around 9:30 in (fast) Ironman, but I'd say they had a good history of base fitness behind them, talent, and were willing to hurt themselves in training. Unless your surname is Wellington, it's a bit of a journey.
Going back to the kind of times you require. You'll first of all need to be able to swim at least under 1hr and pref
As I would a short(er) distance running or triathlon event to a point ie gels and the odd bar washed down with electrolyte drinks. If you're optimising your running pace (and almost redlining) then you need those fast release sugars and salts.
I could usually get to circa 50miles at a decent pace this way. For anything longer I'd start to introduce more cal packed foods inc a higher % of fats and proteins. The pace would invariably drop along with the HR at this point anyway so the stomach is under a little more pressure to process. Mentally it gets tricky of course so some of your favoured snacks come into their own here.
As already mentioned you can assist the stomach in various ways. I would take a zantac before the race, omit fizzy drinks, and have some ginger later on (not that I felt it made a difference).