Just a note, that you know from who the last advice came.
Bill Graham is in his age of 68 the holder of the US national record for static apnea, with the official time of 7:21 (and he already did above 8 minutes in training).
As for tables, I believe that they would work for you quite well. Their advantage is that they are very well reproducible, so you can easily follow your progress. The main advantage is not really some physiological adaptation, but rather improving of your technique and relaxation skills.
Besides the classical CO2 tables, and besides the simulation exercises Bill advised, you can also try an extreme CO2 table - for example repeating a constant breath-hold (i.e. 45s) with only one single exhale and inhale between the apneas, during 8 or 10 minutes. Make the first attempt with a short apnea (i.e. 30s), but try to keep it always at least 30s at the subsequent breath-holds in the series. If you feel it is too easy, you can add a few seconds at the next one, but you should never go down. At the last apnea in the series, you should have contractions almost during the entire breath-hold, but you should try to relax despite them (not fighting them, but rather going along with them)
I believe that for you especially the CO2 tables would be interesting, since when surfing, your body is already hypercapnic (loaded with CO2), so you do not really fight hypoxia (low O2), but rather hypercapnia (high CO2). With hypercapnic tables you will learn to endure more contractions, and also manage to decontract better despite them and despite the stress or panic.
During the tables you have time to watch your own body reactions, and you will learn that you can endure quite a lot of contractions. It is necessary to think positively about them - they save your life. And the same goes for the feeling of distress or panic - in fact all these aspects are quite positive, because they set the organism into a better oxygen saving mode.
Also empty lungs series are an excellent exercise for improving your psychical endurance - when you start doing empty lungs apneas over 1 or 2 minutes, you will be much less afraid when a wave surprises you without full lungs. You can also combine empty lung apnea with hypocapnic exercises - empty lung CO2 tables. I have such exercises in my
Training Manager too.
