Hi Jerry,
I don't think that it would be a mistake to go to an fx or taipan 4.9. However, any boat that you get will probably get more wear and tear as you figure it out. Such as moving it around the beach, trailoring, righting it etc. I think the taipan 4.9 is the better boat.

I definitely would not recommend a Tiger for a new single handed sailor.

As for righting, not sure, but I think that it should be ok.

I would definitely choose the Taipan over the fx because I think that the formula classes are the way of the future (F16HP) over one-manufacturer classes.
Also I think that the 4.9 is more versatile (uni/sloop/spin)

And yes you don't have to sail uni if you are singlehanded. You might want to put a furler on your jib for when the wind comes up. I can sail my Nacra 6.0na single handed up to about 15 knots, jib furled, and its a beast of a boat, so the 4.9 should be a lot easier.

Another consideration is what everyone else in your area is sailing. This is important because if (when) you start racing it is better to race against like boats.

Definitely get a ride on each boat you wish to consider.
David