Hi Phil,
welcome aboard, and I concur with Howard's sage advice. Flying with genuine Jetex can be done, but it ain't easy!
The blue pack of pellets are the later Sebel type. These burn hotter than the original ICI formulation and
should not be used with the two aluminium-bodied motors as they could burst.
Original ICI pellets are out there but they are rare! As Howard says, keep the alloy motors and (at least so start with) use the steel bodied motors.
I would but the black Powermax pellets on the roses - I think they are a waste of time.
To seal motors, you can add a smear of silicone sealant to the washer.
There is a video out there about loading motors, see:
Loading Jetex motors
One problem us vintage Jetex fliers have is old fuse. This is now quite rare and doesn't always work. A modern alternative is an electric igniter:
These work well and I have them in stock.