So EL3N is a bit darker than EL11. EL11 is similar to EL13. That leaves EL8 sounding similar to the EL3N.
EL8 ~ EL3N and EL11 ~ EL13 correct me if I'm wrong. I think I'll restric myself to only the EL3N & EL11 then since they seem to be easier to source
In my experience, it is not this simple. Tubes manufactured in different factories by different companies sound different. So for example, EL11 manufactured by Valvo, Telefunken, Tesla, RFT, Tungsram will likely all sound different.
And therefore, when making comparisons such as these, it is necessary to know the factory. Most, if not all Philips EL3N were manufactured in a factory located in Vienna, Austria (WIRAG). In my experience, WIRAG tubes are in fact warmer and darker than tubes manufactured by Telefunken. But that does not mean that all EL3N are darker than EL11. In each case, it depends on the factory.
If EL11 and EL13 were manufactured in the same factory, for example, Telefunken, it is very likely than will sound very similar. If EL3N and EL8 were manufactured in different factories, they will likely sound different.
Therefore, in each case, I urge those of you posting your impressions to identify the factory. And it is important to understand that in many cases, the brand does not accurately indicate the factory. So it will often be necessary to do a little research. But you are not alone. Many here can help you.
Cheers