How many Lefties to Lefty & Righty Pitchers face?

Anyone have any rules of thumb to share? I was thinking...

Lefty pitchers face ~ 25% Lefty Batters
Righty pitchers face ~ 55% Lefty Batters

...but I looked at some data from a 2016 league I'm in and it seems like there are more right-handed batters than that? Any thoughts? ...I'm trying to figure out how often pitchers use each side of their card.

Many factors affect your question, such as:

1. Salaries. Higher salary caps result in more platooning.
2. Player set. In some sets, righty pitchers will face more left-handed hitters. However, in my recently completed 60s league, my right-handed pitchers faced quite a few more right-handed hitters (e.g., Drysdale faced over 63 percent right-handed hitters).
3. Is the the starter a regular starter or a spot starter? In the same league, lefty Gary Peters who started every four days faced 22 percent left-handed batters. Marcelino Lopez, who I only used against left-leaning teams, faced 28 percent.
4. Obviously, rosters will vary even when using the same set, and this will have an influence.
5. A pitcher with an extreme bias (e.g., 6R can expect to face more lefties).
6. A ballpark with an extreme homerun bias may encourage opposing managers to tweak their lineups to take advantage.

Hey Riggo, Luckyman writing, hope you're doing well.

My own default for 20XX is 24/76 and 53/47, but as coyote writes, sometimes the set orders a different ratio. In 2016, I believe that there were some very popular hitters--and some very good bargains----among right-handed hitters, so I suspect many owners went with right-handed stadiums in the hope of drafting them, so it all tilted a bit the set towards right-handed hitters. I didn't look at the 2016 set extensively, but I would be surprised if the same pattern happens.

I would add that, with the new ability to set different lineups against reverse rhp or reverse lhp, I regular see teams carrying a few 1M players that they can throw against more extreme pitchers. So a 3lh-6rh team can become a 4-5 team against a 7R rhp...

Thanks Luckyman & Coyote.

Yeah, what I was looking for were default assumptions for % vs L and vs. R. My default assumptions are similar.

It will be interesting to see if the greater % of right-handed batters holds up. It does seem there are now more right-leaning parks, whereas, back in early 2000s it seemed like there were always more lefty-leaning parks.