[Roadsters] sparkplugs and hardtops

[toolmansj2 at comcast.net]

Hi Everyone I need your words of wisdom. 

When I look on the NGK web site for 1969 u20 it is telling me to use bpr5es or bpr5ey. 
Everywhere else I look it says to use 6 series plugs which are a step colder. Is there any logic to this? 

On another note I have a port hole hardtop that needs a seal are there any good sources for a new seal. 
I think the top was made by custom hardtops out of so cal 
Thanks For The Help 
Shaun . 

1969 2000 U20