I bought one of the cheap split screens off ebay and can honestly say it was the biggest waste of money I have spent on my camera (apart from 2 useless flashes).
I also buggered up my original focus screen when changing them over (and back again) as I touched both of them with my fingers before realising that A) it leaves bloody great fingerprints on both, B) you get LOADS of dust in the viewfinder unless you do it in a fairly dust free enviroment and C)when you try to clean the dust off the screen it makes it 50 times worse.

All in all not a pleasant experience and one I am still living with everytime I look through the viewfinder.

Saying that though, its a fairly simple process

no matter how good the lens is there is no point buying the 70-210mm Tamron if you are wanting 300mm (and it is a cracking lens).
Personally I would go for either the Pentax DA 55-300mm or if you can run to it then the DA*300mm.

Wouldn't like to put a kit on Ebay so that I can use my 10% paypal discount would you?
Only 1 day left until it expires.

Im no expert but it just looks like a big red blob to me.
I think you need something with a bit more detail in the background when doing selective colouring to give the person looking at the photo something to compare the colored bit with.

Fun doing them though isn't it

First thing I would ask is what is your max budget?

Actually THIS may be more appropriate

Link to some info

Ummmmmmm

Do Jessops give you a 2 year warranty like SRS?

Im waiting to see some pictures taken with it.