Screw sizes for 2x6 (50x150mm) joists on decking ?

Can anyone advise on a sensible screw length for use with 2x6" joists on decking. I usually over engineer things but given the cost of these exterior grade screws and the number required, not this time.
Have looked at 100mm and 150mm, 100 looks a bit short (only 50mm into end of joist by the time its gone through the 50mm of the cross member) and 150 a bit long (can't see anything in between).
The deck sections will be 2mX2m and supported on posts at each corner so the screws going through the outer cross members and into the end of the joists will be taking the weight of the joists plus decking planks.
I was thinking 2 screws per joist end, but any advice along with that on length is greatly appreciated.
Thanks in advance, signed, 1st time deck builder.

try pulling 50mm of screw out of the timber.

what are you planning on building upon the deck anyhow.

100mm will be fine, we normally use 95mm ring nails shot fired into the timber. Personally i would use rather more than two screws. We normally fire about 3 through the end of the memebr, and three skew nailed on either side of the joist, with another skew nailed through the top of the memeber. Nails and screws are cheap, ,time spent re doing it isnt!

Thanks guys, I have also read somewhere else that 50mm of screw into the joist end is sufficient, but from your experience Thermo, sounds like more than 2 per joist end is needed.
Noseall, not planning to build anything on top of the deck, its just getting the morning sun and having breakfast on.