These are all very desirable outcomes and were also the reasons for my own plans to implement an oil filled system.
Since my stern tube is steel
I intend to weld stainless steel
flanges to both ends of it and mount the tapered roller bearings and seals in bolt on housings. The required pre-loading will be achieved by adjusting the length of the bushes on which the seals bear.
One of the problems I experienced with the predecessor to the gland arrangement illustrated above was that I used sealed, single
row roller bearings and the shaft rotated inside them. This necessitated bearings with some sort of shaft locking arrangement. The Y bearings were the only ones available locally which have grub screws to lock onto the shaft.
I don't have a problem with transmitting the prop thrust through the gear
box and engine
mounts to the hull. Marine
gearboxes and engine
mounts are designed for this, although the system I propose with tapered roller bearings would do this directly via the stern tube - tapered roller bearings are designed for both radial and axial loading.
Should the shaft gland arrangement in the above image prove effective I may consider using just a miss-aligning spherical roller bearing on only the prop end of the shaft, these are supposed to allow shaft flexing without consequent damage to the bearing. You might consider this as a possible solution which would not need a thrust bearing.
I have a small lathe and mill aboard the vessel and enjoy mucking about in boats so doing and redoing these things to get them right is actually recreation for me. I don't mind doing them over a number of times and trying different things as I find it all interesting, it is a gainful way of filling my days at anchor
when I am not cruising and there is a great deal of satisfaction to be gained from achieving a successful outcome without recourse to the excessively expensive marine