Must be a fixed spool thing. I pendulum cast 66lb power pro with an 80lb mono leader on a Saltist 20 and a 525 Mag and I've never had even a hint of a problem.
As for the last bit all I can say is Eh? Basic physics tells you there is no "pushing" whatsoever going on in a cast - the acceleration then momentum of the lead pulls the line off the spool for both a multiplier and a fixed spool. Problems can occur with a multiplier when the spool is running too fast and the momentum of the lead is insufficient to match the acceleration of the spool (overrun and crack-off) but that is down to a poorly set-up reel and / or crap casting technique, not the main line being too light to push the leader through the rings
It is a fixed spool thing as the line comes off in coils if you watch a video on slow motion you can see how big them coils are, mono leader works fine if you get the correct amount on and the mono gets through the eyes as quick as possible, just out of curiosity Stewart do you not loose the sensitivity of the braid having a mono leader? And does the braid not just wear through the mono when pulling out off snags? I have used braid on a multi but only with a braid leader which I found brutal to cast and control as it's not like mono were if the reels a bit fast you can just thumb it then knock the mags on a bit next cast, do you just start with a slow reel then adjust
