Question: Which vocalist was part of more bands, Spencer Chamberlain or Donnie Van Zant?

Context articles: The Ballad of Curtis Loew
Van Zant
Ronnie Van Zant Memorial Park
38 Special (band)
Ken Lyons
Spencer Chamberlain
Donnie Van Zant
Johnny Van Zant
Southern by the Grace of God
Ronnie Van Zant

"The Ballad of Curtis Loew" is a song written by Allen Collins and Ronnie Van Zant and recorded by Lynyrd Skynyrd.
 The song was first released on the band's 1974 album, "Second Helping" and again on their compilation, "The Essential Lynyrd Skynyrd" and later on "All Time Greatest Hits".
 It is on many of their compilation albums and before the Lynyrd Skynyrd plane crash, was performed once live on stage.
 Ed King says, "The original version of the band only played 'Curtis Loew' one time on stage.
 We were playing in a basement in some hotel and thought we'd try it.
 We never played it again until the Tribute Tour with Johnny Van Zant."
Van Zant is an American musical duo composed of brothers Donnie Van Zant and Johnny Van Zant.
 Both are brothers of the late Ronnie Van Zant, former lead singer for the Southern rock band Lynyrd Skynyrd.
 Johnny became the lead vocalist for the reunited Lynyrd Skynyrd in 1987, and Donnie was also the leader and vocalist of .38 Special.
The Ronnie Van Zant Memorial Park is a public memorial park located in Lake Asbury, Clay County, Florida.
 The park was built in memory of Ronnie Van Zant, vocalist of Southern rock group Lynyrd Skynyrd, who died along with numerous other band members and crew in a 1977 plane crash.
 The park was funded by fans and family of the band, and features a number of facilities including tennis courts, fishing ponds, a disc golf course and picnic areas.
38 Special (also written .38 Special) is an American rock band that was formed by neighborhood friends Don Barnes and Donnie Van Zant in 1974 in Jacksonville, Florida.
Kenneth Leo Lyons (March 17, 1953 – May 20, 2012) was a bass guitarist and founding member of the southern rock band 38 Special.
 He was born to mother Joyce Lavelle Godwin Lyons and father Clynn Leo Lyons in Jacksonville, Florida.
 He founded 38 Special with Don Barnes, Donnie Van Zant, Jack Grondin, Steve Brookins, and Jeff Carlisi in 1974.
 He was a member of 38 special from 1974 to 1977.
 He only played on their self-titled debut album.
 He left 38 Special in 1977, before their first album was released.
 Lyons was replaced by Larry Junstrom, who continued to play in 38 Special until his retirement in 2014.
 Lyons died on May 20, 2012 at the age of 59 at the Wake Forest Baptist Health Center in Winston-Salem, North Carolina.
Spencer Chamberlain (born January 4, 1983) is an American musician, best known for being the current lead vocalist for the metalcore band Underoath.
 Before fronting Underoath, Chamberlain was the vocalist for the band This Runs Through in which his brother, Phil Chamberlain, was the drummer (who is also the drummer for To Speak of Wolves).
 He is currently the vocalist of Sleepwave.
Donald Newton "Donnie" Van Zant (born June 11, 1952, in Jacksonville, Florida) is an American rock vocalist/guitarist.
 He is best known for being a member of the band 38 Special, from its formation in 1974 until 2013.
 He is the middle of three brothers: his older brother Ronnie was the original lead singer for Lynyrd Skynyrd who died in a 1977 plane crash in Mississippi along with five other members and associates of the band; his younger brother Johnny is the current Lynyrd Skynyrd's lead singer since 1987.
 Donnie and Johnny also perform together from time to time as the group Van Zant.
John Roy "Johnny" Van Zant (born February 27, 1959) is an American musician and the current lead vocalist of Southern rock band Lynyrd Skynyrd.
 He is the younger brother of the late Lynyrd Skynyrd co-founder and former lead vocalist Ronnie Van Zant, and of the 38 Special founder, Donnie Van Zant.
Southern by the Grace of God is a live album by southern rock band Lynyrd Skynyrd, this live concert was a tribute by Lynyrd Skynyrd to the members of the band who had died in the 1977 plane crash.
 The plane crash killed frontman Ronnie Van Zant, guitarist Steve Gaines, backing vocalist Cassie Gaines and road manager Dean Kilpatrick.
 This is the first album produced by the band after the '77 plane crash.
 The band's lineup was re-worked into a second-generation Skynyrd.
 The changes include: Johnny Van Zant, younger brother of Ronnie Van Zant, taking over on vocals, Ed King, who departed the band during a 1975 tour and Randall Hall, who replaced the paralyzed Allen Collins.
 The three (King, Hall along with founding member Gary Rossington) re-form the famous triple-lead guitar attack of the original band.
 New background vocalists Carol Bristow and Dale Krantz-Rossington were added to take the place of the original Honkettes.
Ronald Wayne Van Zant (January 15, 1948 – October 20, 1977) was an American lead vocalist, primary lyricist, and a founding member of the Southern rock band Lynyrd Skynyrd.
 He was the older brother of two other rock vocalists: current Lynyrd Skynyrd lead vocalist Johnny Van Zant, and Donnie Van Zant, the founder and vocalist of 38 Special.
 He was the father of singer Tammy Van Zant, and cousin of musician Jimmie Van Zant.