Thanks for the input guys:-
Firstly, I can use the chest loading pad with my 75cm gun but not a chance with my 90cm, my arms are way too short!
Secondly, DafyddRees demonstrated the technique that Magpie posted when we were out last weekend - worked fine on his gun with 16mm bands but not a chance with my 20mm ones... they are just way, way too stiff.
Maybe it's just that they're new??? The pulling from the hip method works, it just that the gun twists a bit under the pressure meaning that I have trouble fitting the metal wishbone in neatly - it would be a lot easier if I had dyneema wish bones.
Are you using Seatec 20mm bands on your Gabbiano, Broseidon? I recall that you are particularly strong individual - a body builder in fact. So the comment about technique might be right, I found women climbers often have better technique because they have less strength available they have to...but there might be other issues...
I have 20mm RA bulk rubber on my RA 90 (which I suspect it is actually 3/4" USA bulk rubber). It is a bear to load. I think probably tougher than euro-bands perhaps because the centre hole is smaller, so more rubber. However after persevering with it, I've come to the conclusion that it isn't strength so much as pain and bruising that is the issue. I came back with black & blue upper abs and chest after week of spearing a couple of years ago. The RA has no loading butt and quite honestly the otherwise excellent Elios wetsuit's loading pad isn't up to the job (and it's too soft and about 3" too low for me) in this case. I get bruised and then the tendency is to try loading in another, less optimal spot (you mentioned twisting) - and so things deteriate. I now use
a thick flip-flop insole strapped to my chest under the wetsuit (RA actually sell a reasonably priced strap-on loading pad, which you could wear over or under your wetsuit).
It makes a huge difference, and I use it will my other spearguns too. Without the pain or fear of bruising, you can concentrate on loading technique; it all suddenly becomes a lot easier. I wonder if African wetsuits (e.g. Predator) have tougher loading pads?
My RA came with a single 16mm band and that worked well and was plenty powerful enough to send the spear right through every fish shot with only 2 exceptions (both were gill plate shots on large fish and one was with the 20mm rubber). I recently bought enough 16mm rubber to re-equip my 3 spear-guns with 16mm rubber when the rubbers next need to be replaced -- although bulk rubber seems to last much longer, especially the thick stuff -- of course
I think 20mm rubbers put a lot of people off spearfishing. A significant number of the used spearguns on eBay are equipped with 20mm rubber and most spearguns are not sold with 20mm rubbers. I reckon a single 16mm bulk rubber on a 90cm gun is more than enough for most UK fishing. Not sure about shorter guns, my Omer XXV 75 & 90 have 18mm screw-in bands which seem to work well.