Hi Ivan
I dont know anything about the sporosub handles besides what you told me those guys in the auzzi dive shop said. i havent even seen a stealth railgun. whatever i say would be speculation, so id rather keep quite.
About using the 150, i dont know what the best setup would be, but i think that 2 sixteens is more popular. abri would know .at the dive factory,all the long guns that were waiting for shipment had single sixteens on them. i think that a single 20mm would just be too hard to load with that long gun, to get the same power that you want. like you cant bench press 100 kilos just because you can bench 50 twice
. you said that you welded a loading tab on to the spear? id avoid doing that because the weld may weaken that point, especially when the spear is going to be around 2m long.
and you say that you put a 50cm 20mm rubber on your 110! man thats very short. thats the reccomended lenght for the 16mm.
i went from a 50cm sixteen to a 75cm 20mm on my 110. the sixteen was hard to load, but do-able, but the longer 20mm is much tighter. unless the rubbers are different. i have seen two types of 20mm rubber. the one we get from dive factory is black outside with clear latex on the inside, the hole for the wishbone is the same size as for a sixteen. the other type is all black rubber with a bigger hole.
so if the rubbers you are using is the same as ours, then thats incredible, even with a loading tab. ask SASpearo about the 20mm on his 120. :t
cheers
mark