WHAT SIZE RADIATORS

Hi everyone , just need info on what type and size radiators i should use in my house , i have spoken to 2 plumbing shops, and getting different info regarding the size's and BTU outputs so here is the rooms sizes , with no internal or external wall insulation, might be down the line , however had to take out all the existing rads and gun barrel pipe , as it was in since 1972 with oil , and was changed to wall mounted 120 k b.t.u. gas boiler in 2002 , but the pipe work was not changed, and was now in a very bad way

Kitchen 15ft x 9ft. 2 outside cavity block walls 1 wall is 4ft from next door
Dinning, 13ft x 11ft 1 outside wall , with an open fire, use from nov to march
Lounge, 13ft x 11ft 1 northfacing wall
Hallway 17ft x 7ft 1 fullwidth front door unit north facing
Landing 9ft x 4ft no outside walls
Bed R 1 13ft x 11ft 1 outside wall
Bed R 2 13ft x 11ft 1 outside wall north facing
Bed R 3 8ft x 7ft 1 outside wall " "
Bed R 4 12ft x 8ft 2 " " " "
Bed R5 8ft x 8ft 2 " " south facing
Bath R1 8ft x 7ft 1 " " " "
Bath R2 5ft x 6ft 1 " " north facing

Would like to use 500 high double panel Rads down stairs
and Single panel rads upstairs, ? or if you have a better suggestion i am open to it, i want to use termo valves every where except the bathrooms ?
and 2 zone system where i can use the gas to heat the hot water only in the summer,
hope i have covered every thing , thanks to everyone who can help ,